Rudinıs text deŜnes a Borel set as one which can be obtained by a countable number of operations, starting from open sets, each operation consisting in taking unions, intersections, or complements. I can understand how the collection B of all Borel sets in R^k is a sigma-ring. However, how can one prove that B is the smallest sigma-ring which contains all open sets? It would appear that B is a sigma-algebra as well, since it closed under complementations. Is this correct? Lastly, can the above conclusions concerning B hold for === Subject: Re: Sigma-ring proof > Rudinıs text deŜnes a Borel set as one which can be obtained by a > countable number of operations, starting from open sets, each > operation consisting in taking unions, intersections, or > complements. I can understand how the collection B of all Borel > sets in R^k is a sigma-ring. However, how can one prove that B is > the smallest sigma-ring which contains all open sets? It would > appear that B is a sigma-algebra as well, since it closed under > complementations. Is this correct? Lastly, can the above > conclusions concerning B hold for spaces other than R^k? Many If a collection S of sets is closed under complementation, then the sigma-ring generated by S will also be closed under complementation; i.e., the sigma-ring generated by S coincides with the sigma-algebra generated by S. In particular, in any topological space, the sigma-ring generated by the open sets together with the closed sets is a sigma-algebra. Now, in a metric space, every closed set is a G-delta set (intersection of countably many open sets); in that case, the sigma-ring generated by the open sets will also contain the closed sets, and it is a sigma-algebra. === Subject: Re: Sigma-ring proof > Rudinıs text deŜnes a Borel set as one which can be obtained by a > countable number of operations, starting from open sets, each > operation consisting in taking unions, intersections, or > complements. I can understand how the collection B of all Borel > sets in R^k is a sigma-ring. However, how can one prove that B is > the smallest sigma-ring which contains all open sets? It would > appear that B is a sigma-algebra as well, since it closed under > complementations. Is this correct? Lastly, can the above > conclusions concerning B hold for spaces other than R^k? Many > If a collection S of sets is closed under complementation, then the > sigma-ring generated by S will also be closed under complementation; > i.e., the sigma-ring generated by S coincides with the sigma-algebra > generated by S. In particular, in any topological space, the > sigma-ring generated by the open sets together with the closed sets is > a sigma-algebra. Now, in a metric space, every closed set is a G-delta > set (intersection of countably many open sets); in that case, the > sigma-ring generated by the open sets will also contain the closed > sets, and it is a sigma-algebra. === Subject: Re: Sigma-ring proof Your question is not very clear; usually one deŜnes the Borel set B of R^k as the smallest sigma-algebra (or sigma-ring, same thing here since the space R^k itself is open and whence belongs to B) containing the open subsets of R^k. Now your deŜnition deals with constructing sets using certain operations. (Btw, you didnıt deŜne that process precisely and you should do it (thatıs not thaaaaaat easy to formulate)) What you can say is that any sigma-ring containg the open sets of R^k will also contain (by deŜnition) all the sets constructed by using the previous process. The resulting set (being also a sigma ring) is therefore the smallest sigma ring containing the open sets. This is trivial. === Subject: Re: Egyptian topology on Q > >Oh yes, 1 is isolated. > For each j in N, pj in S^j is mapped to sum pj, where > when pj = (u1,..uj) in S^j, sum pj = u1 +..+ uj ? > Why is 1 isolated? It is in lower limit topology subspace Q/[0,1], > but why is 1 isolated by the quotient deŜnition for your space? > Theorem of Sierpinski (circa 1920) > A space S is homeomorphic to the rationals if it is: > countable, 2nd countable, regular T0, free of isolated points. > The more I think about this, the more I think that this Egyptian > topology is just the half-open interval topology. In that case, this > leads to an interesting counter-example (of a countable locally > compact space mod a closed equivalence relation whose quotient is > Hausdorff but not locally compact). > Can anyone give me a reference for Sierpinskiıs theorem? > It was discussed, not this year, at sci.math and also > Ask-a-Topologist, http://at.yorku.ca/topology > in the form for topology. Use their search engine. > If you understand proof posted there, would you help to clarify it? > Iım muddled about the description used to set up the order upon the > elements. I may look at it, but unfortunately my earlier post was wrong and the topology is deŜnitely not the half-open interval topology. Any set of rationals the form {a_1, a_2, ...} that satisŜes the following conditions is closed, while it converges to 0 in the half-open interval topology: 1. 1/(n+1) < a_n < 1/n 2. length of a_n > n. The reason (roughly) is that when you look at the inverse image of that set in S^k, there are only Ŝnitely many since you get only the Ŝnitely many elements whose length is k or less and such a set is closed and does not contain (0,0,...,0,k). Hence the inverse image in any S^k is closed so it is closed by deŜnition of the quotient topology. This is not what I wanted, but I have to live with it. As a result, Sierpinskiıs theorem is of no help. === Subject: the math fails me I canıt post these equations, they are too long. However, if any of you can visit where theyıre at, http://mypeoplepc.com/members/jon8338/polynomial/ and tell me what I did wrong? jongiff2000@yahoo.com As far as I can tell, the math is perfectly correct, but the answer just doesnıt make sense. Jon === Subject: Re: the math fails me > I canıt post these equations, they are too long. > However, if any of you can visit where theyıre at, > http://mypeoplepc.com/members/jon8338/polynomial/ > and tell me what I did wrong? jongiff2000@yahoo.com > As far as I can tell, the math is perfectly correct, but > the answer just doesnıt make sense. What standard tells you the math is perfectly correct? If the answers are wrong, the math is wrong. QED > Jon Still beating a dead horse. -- There are two things you must never attempt to prove: the unprovable -- and the obvious. -- Democracy: The triumph of popularity over principle. -- http://www.crbond.com === Subject: Re: the math fails me > As far as I can tell, the math is perfectly correct, As far as *I* can tell the math is nonsense. You see, real math has sentences explaining what is going on. And perhaps a few equations if needed. === Subject: Re: the math fails me > I canıt post these equations, they are too long. > However, if any of you can visit where theyıre at, > http://mypeoplepc.com/members/jon8338/polynomial/ > and tell me what I did wrong? jongiff2000@yahoo.com > As far as I can tell, the math is perfectly correct, but > the answer just doesnıt make sense. > Jon Back in grad school, we used to drink Sneaky Petes before lectures (Sloe Gin Ŝzzes). After four or Ŝve, everything made sense! John === Subject: Question on SemiDeŜnite Programming Hi all, I have a question on a basic semideŜnite programming problem. Let B=B_0 + lambda_1 B_1+...+lambda_n B_n, where each B_i is a real symmetric k by k matrix and lambda_1,...,lambda_n are parameters. The problem is: How to Ŝnd the lambda_i such that B is positive deŜnite (or semideŜnite (psd)) ? I know that B is psd iff all eigenvalues are nonegative and that if we consider the characteristic polynomial F(y) of B which is F(y)=y^k+b_{k-1) y^{k-1)+...+b_0 then by Descarteıs rule of signs F(y) has only nonnegative rules iff (-1)^{i+k}b_i ge 0 for all i=0,...,k-1 (b_i are function of lambda_1,...lambda_n). So the goal is to Ŝnd lambda_i such that the set S={(lambda_1,...,lambda_n) in R^n | (-1)^{i+k}b_i(lambda_1,...,lambda_n) ge 0} is nonempty and a point is S is a solution to the initial problem. Now, my question is how to check that a set like S is nonempty ? and how to Ŝnd necessary (and/or sufŜcient) conditions on the B_i such that S is nonempty ? thank you. === === === Subject: Re: Cosets > Can anyone suggest a good text book to study about cosets....I am > totally confused about them. > Fraleighıs book is pretty good. ?? An entire book all about cosets? Are we thinking of the same notions of cosets? Subsets of a group of the form x.H where H is some subgroup? Herman Jurjus === Subject: Re: Carmichaels theorem >[...] >Can you see that Carmichaelıs function is just the LCM of the >values phi(q), where q ranges over the prime power divisors of n? >[...] > Not quite. Carmichaelıs function is the exponent of the prime residue > class group mod n, which in turn is the LCM of the exponents of the > prime residue class groups mod q, where q ranges over the prime power > divisors of n. Now, those exponents are phi(q), indeed, if q is odd or > q=2^e, e<3, since the underlying group is cyclic in this case. If q=2^e with > e>=3, this is no langer the case and the exponent is only phi(q)/2. This > accounts for the weird deŜnition of lambda(n). -- Gerry Myerson (gerry@maths.mq.edi.ai) (i -> u for email) === Subject: Re: JSH: Math journal review === >Subject: Re: JSH: Math journal review >did they give you any editorial feedback, or >did they just cave into the assembled masses >of Usenet? > do you think Ullrich called him a honky? >>Argyros already edits several mathematical journals, including I didnıt write that. Idiot. >--Give Earth a Trickier Dick Cheeny -- out of ofŜce, after gigayears! >http://www.benfranklinbooks.com/ >http://members.tripod.com/~american_almanac >http://www.wlym.com/pdf/iclc/HowTheNation.PDF >http://www.rand.org/publications/randreview/issues/rr.12.00/ >http://www.rwgrayprojects.com/synergetics/plates/Ŝgs/plate02 .html -- Mensanator Ace of Clubs === Subject: Re: polya-burnside enumeration > Can anybody furnish me with some tips/references on applications of the > polya-burnside enumeration method to problems involving symmetries of > three-dimensional shapes? (This is part of my ongoing attempts to become more > geometrical.) Some broad hints would probably be enough to get me started. Mucho > appreciado. > Peace Try Tuckerıs Applied Combinatorics. Many 2d-applications some 3d. There is really no difference between the 2d and 3d cases except in description of the symmetry groups. For some discussion of 3d symmetry groups of Ŝgures try Michal Artinıs Algebra, Ch 5. Best, Andy === Subject: Re: Name of this group? by support1.mathforum.org (8.11.6/8.11.6/The Math Forum, $Revision: 1.9 primary) id i4P52ne02553; >My group appears to be QxC_3. Here some more info: >The above group is isomorph to a subset of the >algebra over the reals generated from the factor group >F = QxQ/C(QxQ) , C = group center. Now, there is more to this: >There are actually two (and very likely only two) such groups >on this space isomorph to QxC_3 and hence to each other. >Multiplying elements between these groups amongst themselves >will, in all likelyhood, produce a single parent group which >should have more than 60 or so elements at the very least- I will >check this soon. 60 or so appears to have been a major understatement. I now have the order of this (somewhat mysterious) parent group to be at: 8*32 + 32 + 2 + 2*a where a very reasonable guess of a is the number of ways of multiplying the following row vectors pointwise to create new vectors. (-1, 1, 1, 1, 1, 1, -1, 1, 1, -1, -1, 1, 1, 1, 1, 1) (1, -1, 1, 1, 1, 1, 1, -1, 1, 1, 1, -1, -1, 1, 1, 1) (1, 1, -1, 1, 1, 1, 1, 1, -1, 1, 1, 1, 1, -1, -1, 1) (-1, -1, -1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, -1) (1, 1, 1, -1, -1, -1, 1, 1, 1, 1, 1, 1, 1, 1, 1, -1) (1, 1, 1, -1, 1, 1, -1, 1, 1, 1, 1, -1, 1, -1, 1, 1) (1, 1, 1, 1, -1, 1, 1, -1, 1, -1, 1, 1, 1, 1, -1, 1) (1, 1, 1, 1, 1, -1, 1, 1, -1, 1, -1, 1, -1, 1, 1, 1) That may a lot more than my original guess of 60, but it is still a long shot below the Ŝrst upper bound I was able to Ŝnd for the parent group, which was 8*32 + 32 + 2 + 2^{16} (!) Have a nice evening, C. Dement >Want to see what this group looks like graphically? >Check www.uni-oldenburg.de/~jojo6/Floretions/Floretionspage.html >Let iı (i with an arrow to the right) = [(1,i)] in F > Œi (i with an arrow to the left) = [(i,1)] = [(-i,-1)], etc. > Œijı (a single element written as the > juxtaposition of an i with an arrow to the right with > a j with an arrow to the left) = [(i,j)] >Then the element (i,C_1) in QxC_3 would appear to correspond, >say, to the element Œi + Œiiı + Œijı + Œikı ; the gray >shaded area of Floretıs cube. >Similarly, (j,C_1) to Œj + Œjjı + Œjiı + Œjkı, etc. (could be slightly >mistaken in that (j,C_1) actually corresponds to >ık + Œkkı + Œkiı + Œkjı). >Sincerly, >C. Dement === Subject: Re: Bijections between uncountable sets by support1.mathforum.org (8.11.6/8.11.6/The Math Forum, $Revision: 1.9 primary) id i4P52qJ02661; >> ... >>And thereıs another thing thatıs confusing me. Though no topology was >>speciŜed for X and Y, the problem says they are uncountable. When you >>say something about the cardinality of a set, arenıt you automatically >>assuming a topology is deŜned on it? >> Good heavens, no. It would be interesting (I mean this quite >> sincerely) to know how and where you got that idea, in as much >> detail as you can provide. >This is just a point I have some difŜculty to understand. It doesnıt >come from any book. Iıll try to exemplify why it seems to me you got >to have some information about a set to say itıs countable or >uncountable. Again, letıs consider R with the Euclidean metric. I know >2 classic proofs that R is uncountable: You may know only two, but there are many others. In the statement you are given two general uncountable sets - not necessarily those that you know how to prove are uncountable. > One of them is based on the >fact that every real number has a decimal expansion. Then, we can use >that well known proof due to Cantor. But to use this proof, you have >to know that every real number has a decimal expansion, and so you >have to make some assumptions about the objects that form R. I think >you donıt actually need a topology, but at least you need order, you >have to know R is an ordered Ŝeld. > You need to know you can add and multilply 2 elements of R and get another element of R. You do not need the order, addition and multiplication. The proof works just as well for the set of all functions f:N->{0,1} (which, in and of itself, has no inherent notion of order, addition, and multiplication). >The other proof relies on the fact that R is complete (the deŜnition >based on Cauchy sequences), which implies every nested collection of >closed non-empty intervals has a common point. And also relies on the >fact that R has no isolated point. We can also prove that every >compact Hausdorff space with no isolated points is uncountable. >But such proofs are based on topolpgies. The Euclidean metric makes R >into a complete metric space with no isolated points, wich implies >perfect subsets of R are uncountable. If, on the other hand, you take >R with the discrete metric, the that proof based on nested closed >intervals doesnıt work, because, then, every real number becomes an >isolated point of R. And, in addition, as far as I know, itıs >impossible to talk about closed and open sets, Hausdorff spaces and >the like without taking into account some topology. Here is a simple example of another uncountability proof: for every countable set X, P(X) is uncountable (where P(X) is the set of all subsets of X). This is a direct result of a theorem known as Cantorıs theorem. You can Ŝnd the proof in any elementary text on set theory. >>Does it make sense to say a set >>is countable or uncountable if all you know about it is that itıs just >>a set of objects? For example, we can prove R, in the Euclidean >>metric, is uncountable because we know, at least axiomatically, that >>itıs complete, is ordered and every non empty set bounded above has a >>supremum. >> Your because lacks logical force. Consider the entirely similar >> claim we can prove that the singleton {0}, in the Euclidean metric, >> is uncountable because we know, at least axiomatically, that itıs >> complete, is ordered and every non empty set bounded above has a >> supremum. >Yes, thatıs right. But {0} has only one element and itıs and isolated >point, because {0} is open. >>If I only say let A be a set of objects, then thereıs >>nothing one can say about itıs cardinality. >> What deŜnition of cardinality are you using (or do you think you >> are using)? Are you working by yourself, from a book or other written >> source? Are you taking a course? Where do your ideas come from, here? >The deŜnition of cardinality Iım aware of is the one presented in >most Analysis and Topology books. Cardinality is a rather relative >concept, right? We say X and Y have the same cardinality if thereıs a >bijection fron X to Y. And if A is Ŝnite, we say A has cardinality n >if itıs equivalent to the set {1, 2....n}. Right? >I study Math on my own, and Iım trying to get into ponts I couldnıt >study when I was graduating. I may be wrong, but I really canıt see >how someone can say a set is countable or uncountable without having >some information about the set, about the relations between itıs >elements. Of course you need some information, but that has nothing to do with the statement at hand. When someone tells me x is a number I canıt say whether it is even or not unless I have some more information. But that doesnıt mean that the proposition x is an even number is invalid. Your statement should be true (even though it is not true) for all uncountable sets, regardless of whether you can prove them to be uncountable. >If someone tells me that A is a set of objects and asks me >about tıs cardinality, then only honest answer I can give is I donıt >know. If, on the other hand, someone tells you that A is an uncountable set of objects and asks you about itıs cardinality, you can say something: it is greater than Aleph0. >Amanda Cron === Subject: @ HOW DESPERATELY DO THE FRIEDMANS NEED INDIANS !! Comments: This message probably did not originate from the above address. It was automatically remailed by one or more anonymous mail services. You should NEVER trust ANY address on Usenet ANYWAYS: use PGP !!! Get information about complaints from the URL below X-Remailer-Contact: http://80.65.224.85/POL/ In case my abuse address is unreachable: It is because it has been ŝooded by , please contact X-Mail2News-Contact: http://80.65.224.85/ It can certainly be very interesting to watch (friends of Israel) in their hour of need. Will Friedmen display this kind of love and humanity for the poor in Palestine ?? > Making India Shine > By THOMAS L. FRIEDMAN > India just had a stunning election, with incumbents across the country > thrown out, largely by rural voters. Clearly rural Indians, who make > up the countryıs majority, were telling the cities and the government > that they were not happy with the direction of events. I think I can > explain what happened, but Ŝrst I have to tell you about this wild > typing race I recently had with an 8-year-old Indian girl at a village > school. > The Shanti Bhavan school sits on a once-scorpion-infested bluff about > an hourıs drive -- and 10 centuries -- from Bangalore, Indiaıs Silicon > Valley. The students are all untouchables, the lowest caste in > India, who are not supposed to even get near Indians of a higher caste > for fear they will pollute the air others breathe. The Shanti Bhavan > school, with 160 students, was started by Abraham George, one of those > brainy Indians who made it big in high-tech America. He came back to > India with a single mission: to start a privately Ŝnanced boarding > school that would take Indiaıs most deprived children and prove that > if you gave them access to the same technologies and education that > have enabled other Indians to thrive in globalization, they could, > too. > I visited Mr. Georgeıs school in February, and he took me to a > classroom where 8-year-old untouchables were learning to use Microsoft > Word and Excel. They were having their computer speed-typing lesson, > so I challenged the fastest typist to a race. She left me in the dust > -- to the cheering delight of her classmates. > Dust is an appropriate word, because a drought in this area of > southern India has left dust everywhere. These kids -- their parents > are ragpickers, coolies and quarry laborers, said the schoolıs > principal, Lalita Law. They come from homes below the poverty line, > and from the lowest caste of untouchables, who are supposed be > fulŜlling their destiny and left where they are -- according to the > unwritten laws of Indian society. We get these children at age 4. They > donıt know what it is to have a drink of clean water [or use a > toilet]. They bathe in Ŝlthy gutter water -- if they are lucky to > have a gutter near where they live. They donıt even have proper scraps > of clothing. We have to start by socializing them. When we Ŝrst get > them, they run out and urinate and defecate wherever they want. [At > Ŝrst] we donıt make them sleep on beds because it is a culture > shock. Our goal is to give them a world-class education so they can > aspire to careers and professions that would have been totally beyond > their reach, and have been so for generations. > After our little typing race, I asked the 8-year-olds what they wanted > to be. Their answers were: an astronaut, a doctor, a > pediatrician, a poetess, physics and chemistry, a scientist and > an astronaut, a surgeon, a detective, an author. Looking at > these kids, Mr. George said, They are the ones who have to do well > for India to succeed. (See his Web site, www.tgfworld.org.) > And that brings us to the lesson of Indiaıs election: the broad > globalization strategy that India opted for in the early 1990ıs has > succeeded in unlocking the countryıs incredible brainpower and > stimulating sustained growth, which is the best antipoverty program. I > think many Indians understand that retreating from their globalizing > strategy now would be a disaster and result in Indiaıs neighborhood > rival, China, leaving India in the dust. But the key to spreading the > beneŜts of globalization across a big society is not about more > Internet. It is about getting your fundamentals right: good > governance, good education. Indiaıs problem is not too much > globalization, but too little good governance. Local government in > India -- basic democracy -- is so unresponsive and so corrupted it > canıt deliver services and education to rural Indians. As an Indian > political journalist, Krishna Prasad, told me: The average Indian > voter is not saying, `No more reforms,ı as the left wants to believe, > but, `More reforms, pleaseı -- genuine reforms, reforms that do not > just impact the cities and towns, but ones which percolate down to the > grass roots as well. > India needs a political reform revolution to go with its economic > one. With prosperity coming to a few, the great majority are simply > spectators to this drama, said Mr. George. The country is governed > poorly, with corruption and heavy bureaucracy at all levels. I am a > great advocate of technology and globalization, but we must Ŝnd a way > to channel their beneŜts to the rural poor. What is happening today > will not succeed because we are relying on a corrupt and socially > unfair system. ------------------------------------------------------------- ---------- On the one hand the conservative Benjamin Disraeli, a passionate advocate of imperial power and glory. And on the other, his lifelong adversary, the liberal William Gladstone, who championed the moral vision of Prince Albert and David Livingstone. Gladstone was driven by a sense of high moral purpose, and a heavy burden of guilt, in part because his own family had once made a fortune from slave labour. As the leader of the Liberal Party Gladstone campaigned for the export of civilised values through commerce, not conquest. Gladstone feels that the empire is there, thereıs not much you can do about it. He doesnıt want to add to it and he believes that imperialism is a creed which can contaminate the British people, make them warlike, aggressive. Whereas he thinks of a world in which there is universal peace. When he looks at imperialism he says this, is this Godly and he decides it isnıt. He sees it as might somehow triumphing over right. And heıs rather frightened, if the British people get entranced with empire theyıll go gallivanting off Ŝghting wars here there and everywhere, spend a lot of money and cease to be a moral force in the world. This view was Ŝercely contested by his great rival, Benjamin Disraeli. Disraeli Ŝrst moved into the Prime Ministerıs ofŜce in 1867 and for the next 15 years he and Gladstone would alternate in power. Disraeli believed in the expansion of the British Empire. He liked to claim that his ancestors had been rich Venetian merchants trading with the Orient and this gave him a romantic enthusiasm for imperial adventures. Disraeli viewed the empire as an extraordinary asset. The empire made Britain a great power, a global power and also enabled it to have plenty of muscle in Europe. And Disraeli of course likes the glamour of Empire. He sees it bestowing prestige on the country. He eventually hopes that the white colonies will not follow the American course but remain emotionally tied to Britain particularly through the person of the Crown. But Victoria was still in mourning. Since the death of Prince Albert she had lost interest in the Empire and all other affairs of state. Victoria went into what I call Purdah I think because she felt incompetent to handle being a Queen. Albert had done the work for her so long, Albert had done everything, thought out everything for her, arranged everything for her that she did not feel she was up to it again. The Queen found some consolation with the Scotsman John Brown. She began writing about him a few months after Albertıs death: I have an invaluable Highland servant who is my factotum here and takes the most wonderful care of me, combining the ofŜces of groom, footman, page and maid, I might almost say as he is so handy about cloaks and shawls. He always leads my pony and always attends me out of doors ... I think she also enjoyed his picking her up in his arms and putting her on her horse. And taking her off her horse again. For the Ŝrst time since Albert, she had a strong, brawny man who held her in his arms. And I think thatıs as far as the sexuality really went. But she enjoyed it To the dismay of her family and government, the Queen and her highland servant became inseparable. A section of press and public called her Mrs. Brown and her absence from public duty was widely condemned. There were cartoons in the newspapers about this, showing an empty throne. There were editorials in the newspapers about it, why are we paying so much money to maintain a Royal Family because the Royal Family is the symbol of the Empire and of Britain and here we donıt have one. It was Disraeli who would rekindle the queenıs interest in public affairs. His relationship with Victoria had begun badly. She saw him as an upstart, an opportunist, what the British call a chancer, but Disraeli with his considerable charm, set out to win her. His ofŜcial dispatches to her were spiced with social gossip and witty anecdotes. Part of Disraeliıs job as Prime Minister was to write an account of what was happening in Parliament and what was going on in the cabinet to the Queen And Disraeliıs letters to the Queen were wonderfully detailed and rather gossipy, and actually rather indiscreet. He probably told the Queen far more than he ought to have done particularly about divisions of opinion. Most people, Prime Ministers, made these letters very brief and rather ofŜcial, but Disraeliıs letters to Victoria were full of sort of protestations of affection and love and loyalty, really saying nothing at all, they were largely sugar, but Queen Victoria lapped it up. Vicky: Mr. Disraeliıs reports are just like his novels - highly coloured. She had never had such letters in her life, she declared, and had never before known everything. Her attitude to the upstart underwent a dramatic change. Mr Disraeli has achieved his present high position entirely by his ability, his wonderful happy disposition ... and I have nothing but praise for him. She sent him primroses that she picked herself. In return, Disraeli gave her a set of his novels. Victoria had just published a book of her own, a reminiscence of her days with Prince Albert at their palace in Scotland. Disraeli was awfully good at just saying the tactful remark that Queen Victoria would enjoy. For example one of the best was Disraeli saying to her, we authors maıam, which was precisely what Victoria longed to hear, that they were both part of the same club of writers. Disraeli bewitched the Queen with his romantic vision of the British Empire. It would have horriŜed Prince Albert. In the future, Victoria and Disraeli would form a powerful alliance for the imperial cause - but it would be some time before their partnership would bear fruit. Disraeli Ŝrst term as Prime Minister lasted less than a year. When he was voted out of ofŜce, the Queen had to send for the leader of the liberals - Gladstone. Victoria began by liking Gladstone, he seemed to be an upright man. He was ambitious but he was also extremely smart. Prince Albert had warmly approved of Gladstone. When the new Prime Minister came to the palace to receive the seals of ofŜce, the Queen recorded her approval: He is very agreeable, so quiet and intellectual, with such a knowledge of all subjects and is such a good man ... But her satisfaction did not last. Gladstone embarked on a whirlwind of liberal reforms that revived conservative instincts in the Queen that had been dormant while Albert was alive. Mr Gladstone is a very dangerous man. And so very arrogant, tyrannical and obstinate, with no knowledge of the world or human nature ... All this and much want of regard towards my feelings make him a very dangerous and unsatisfactory Premier. She was not amused when he proposed that sailors might be permitted to grow beards. And she was horriŜed by moves towards female equality. The Queen draws Mr Gladstoneıs attention to the mad and utterly demoralising movement of the present-day to place women in the same position as men. But it was Gladstoneıs private life that caused Victoria the most concern. Because of his fanatical religion he felt everyone had to be converted to his ways of morality and ethics. He would go out on the streets at night, even when he was Prime Minister, and solicit prostitutes, take them back to their rooms, give them bibles. He would give them money and he would ask them to tread the straight and narrow ways. Victoria got to know this because her maids in waiting told her everything and it repelled her. At one point when Gladstone was to go up to visit Victoria at Balmoral, she sent him a letter telling him that when he arrived it was to be with a new suit of clothes that he had never worn before. It was very clear that she wanted nothing of the degrading atmosphere of his involvement with these ladies of the evening. Gladstone was unconcerned by the Queenıs personal disapproval of him But he was appalled the imperialist ideas she had picked up from Disraeli. His own more liberal views of Britainıs role were conŜdently being put to the test in Africa. David Livingstone had returned to his Dark Continent. This time he had been sent on an ofŜcial mission to Ŝnd a trading route into the interior and to achieve his dream of combining Commerce, Civilisation and the Christian religion. To this end he was provided with generous funds by the British government and accompanied by six British scientists and his wife, Mary, herself a devoted missionary. Livingstone believed that the Zambezi River could become a great highway for British industrial goods. But as they voyaged along the river, the expedition ran into dangerous rapids. VICTORIA: I saw Mr. Disraeli at quarter to three today. He knelt down and kissed hands saying: ŒI plight my troth to the kindest of Mistressesı. The silver-tongued charmer was back in ofŜce. As he had once conŜded to a friend: DISRAELI: You have heard me called a ŝatterer and it is true. Everyone likes ŝattery and when you come to royalty you should lay it on with a trowel. Disraeli always loved the company of women and he was very good at ŝattering women. And I think with Queen Victoria he was able to see that she was lonely. And Disraeli was able to charm her, and to ŝatter her. And I think very importantly one of the things that Disraeli did was to encourage her to take a far more active role in public affairs. The result of this was that basically he had Queen Victoria as an ally particularly when he was Prime Minister. And this was absolutely crucial I think to the success of Disraeliıs Ministry. That the Monarchy was behind it. Disraeli set out to increase Britainıs prestige and expand Victoriaıs Empire, and within a year of taking ofŜce fate dealt him a brilliant opportunity. Just Ŝve years before the Suez Canal had been carved through the Egyptian desert. It permitted ocean-going ships to pass between the Mediterranean and the Red Sea, linking Europe and the East. For Britain it was the lifeline to her greatest imperial possession. India with 400 million people was the largest overseas territory any empire has ever owned. The Queen called it the most precious jewel in her crown and Disraeli feared that a rival power would cut the new imperial artery. The Suez Canal was absolutely crucial to Britainıs Empire. Suez was the jugular vein if you like of the British Empire. It was through the Suez Canal that the route to India, the short route to India which was so strategically important happened. So for Disraeli it was very important and he was quite right in this I think, that Britain should have a controlling inŝuence over the Suez Canal. The shares in the Suez Canal company were owned by a number of French investors and the ruler of Egypt, the Khedive. The Khedive had spent Egyptıs wealth on palaces, museums and railways. Now, he was deep in debt to banks in London and Paris. The Canal showed no prospect of paying a dividend for years and he desperately needed funds. In 1875, he made a secret offer to the British. DISRAELI: Mr. Disraeli with his humble duty to your Majesty: the Khedive, on the eve of bankruptcy, appears desirous of parting with his shares in the Suez Canal and has communicated, conŜdentially ... ŒTis an affair of millions, about four at least but it is vital to your Majestyıs authority and power at this critical moment that the Canal should belong to England. The Khedive now says that it is absolutely necessary that he should have between three and four millions sterling by the 30th of this month! Scarcely breathing time! But the thing must be done! The Queen replied by telegram the following day, approving his course of action but fearing that it would be difŜcult to arrange. Normally, Parliament could have granted a government loan. But Parliament was not in session and a French consortium had already bid for the shares. Disraeli sent his private secretary to seek help from an old friend. Baron Rothschild was head of the great banking family and one of the richest men in the world. The secretary explained that Disraeli needed four million pounds - the price of the Khediveıs shares in the Suez Canal. When? asked Rothschild. By tomorrow, said the secretary. Rothschild picked up a grape, spat out the pips, and said: What is your security? The British Government, was the reply. You shall have it, said the Barron DISRAELI: It is just settled: you have it, Madam. The French Government has been outgeneraled and the entire interest of the Khedive is now yours. The Queen was delighted. Disraeli treated her not only as his monarch but as a woman and a woman of intelligence. security for India! An immense thing. Mr. Disraeli said that my support had been a great help. His mind is so much greater and his apprehension of things great and small so much quicker, than that of Mr. Gladstone. Gladstone was strongly opposed the deal because he thought it would draw Britain into new imperial commitments. He was right. The Suez Canal was to drag the British deeper and deeper into the murky politics of the Middle East. The overlords of the entire region were the Turks but many of their subject peoples were rising against them. Faced with rebellion on all sides, the Turks resorted to mass slaughter. Russia backed the rebels and Disraeli feared that the Turkish Empire would collapse and open the way for the Russians to advance on the Suez Canal. However badly they treated their subjects, Disraeli thought Britain had to support the Turks. But Gladstone thought otherwise. He was no longer leader of the Liberals. He had retired to his country estate where he relaxed by chopping down trees and setting down his thoughts on God. But he was appalled by stories of Turkish atrocities against their Christian subjects. He thought the corrupt and crumbling Turkish empire should be brought to an end. He laid down his axe and took up his pen. GLADSTONE: There is not a cannibal in the South Sea Islands whose indignation would not arise and overboil at the recital of what has been done ... Let the Turks now carry away their abuses in the only possible manner, namely by carrying off themselves ... This thorough riddance, this most blessed deliverance, is the only reparation we can make to the memory of these heaps and heaps of dead; to the violated purity alike of matrons, maiden and of child ... Disraeli called the style of Gladstoneıs protest vulgar, remarking that of all the atrocities Gladstoneıs writings were probably the worst. But Gladstone had caught the public mood and in the House of Commons, Disraeli was forced to choose his words with more care: DISRAELI: Our duty at this critical moment is to maintain the Empire of England. Nor will we agree to any step, though it may obtain for a moment comparative quiet and a false prosperity, that hazards the existence of Empire. Disraeli backed his words with action. As the Russians advanced on the Turkish capital, he dispatched a British ŝeet, led by the most powerful battleship in the world, HMS Devastation. Public opinion swung to Disraeliıs side. SINGERS: We donıt want to Ŝght but by Jingo if we do, Weıve got the ships, weıve got the men, weıve got the money, too! War fever swept through the pubs and music halls of Britain. The British may not have liked what the Turks were doing to their Christian subjects but they shared Disraeliıs determination to stop the Russians. Fearful of war with Britain the Russians agreed to negotiate. Disraeli set off to attend peace talks. He returned in triumph. His diplomacy had forced the Russians to halt their advance on the Middle East. The lifeline to India was secured. Victoria shared the public rejoicing and decided it was the right moment to claim what she considered to be long overdue. VICTORIA: In common conversation I am sometimes called Empress of India. Why have I never ofŜcially assumed this title? I feel I ought to do so and wish to have preliminary inquiries made. Disraeli introduced a bill in Parliament to bestow on Victoria the title: Queen-Empress of India. Gladstone led the opposition, calling the move: GLADSTONE: Theatrical bombast and folly. But the title was granted and the Queen was delighted. She expressed her gratitude by making Disraeli an Earl. if you like, embellishing the British Monarchy. And at the same time the Queen is given a new sense of responsibility. She is deeply interested in India. Immediately she is made Empress she sets out to learn Hindustani. Doesnıt make much headway but a lot of good will there. And she also hires Indian servants. Between them, the Queen-Empress and her newly ennobled Prime Minister appealed to an imperial spirit that was spreading through large sections of the British public. An aggressive spirit, ŝexing British muscle and lording it over the world. Gladstone continued to oppose it. He called it Showy imperialism. DERBY: Disraeli believes thoroughly in Œprestigeı and would think it in the interests of the country to spend 200 millions on a war if the result was to make foreign States think more highly of us. The Queen backed Disraeli to the hilt. VICTORIA: If we are to maintain our position as a Ŝrst rate power, we must with our Indian Empire and large colonies be prepared for attacks and wars somewhere or other CONTINUALLY But the strain of this imperialist policy was beginning to show British forces in southern Africa had clashed with the most powerful warrior nation on the continent - the Zulus. At the battle of Isandhlwana 600 British soldiers were wiped out to a man. It took 17,000 British reinforcements armed with the latest artillery to defeat an enemy armed largely with spears. Back in England a powerful voice was raised in protest. GLADSTONE: Remember the rights of the savage as we call him. Remember that the happiness of his humble home. Gladstone was no longer in control of Parliament, so he appealed directly to the British people. GLADSTONE: The sanctity of life in the hill villages, is as inviolable in the eye of Almighty God as can be your own. The power of his oratory drew vast crowds. Ten thousand Zulus had died, he claimed . GLADSTONE: For no other offence than to defend against your artillery with their naked bodies their hearths their homes, their wives, their families ... ROY JENKINS: I mean it is one of the great mysteries about Gladstone, how his oratory was so effective. Because he wasnıt a tremendous phrase maker and he didnıt talk down to his audiences, he rather talked up to them. And yet he held them for these very long periods, an hour and a half was quite normal in great mass meetings. I think it was essentially his physical presence, the ŝash of his eagleıs eye. The drama of his gestures, the cadence of his voice. The Queen was outraged. She complained in her journal: Mr. Gladstone is going about like an American stumping orator making most violent speeches. But to her surprise and dismay Gladstone had struck a popular chord. Once more, he had appealed to the British sense of justice and fair play. They voted the Liberals back into power with a massive majority. imperialism he represented. GLADSTONE: It is like the vanishing of some magniŜcent castle in an Italian romance. Prince Albert would have shared Gladstoneıs pleasure at the dismissal of Disraeliıs war mongering government. But Victoria had turned her back on Albertıs moral vision for the Empire. She stubbornly refused to accept Gladstone as her new Prime Minister. ---------- Cecil Rhodes helped by Jewish Maximes - the weapons of mass murder ----------- Africa. The Dark Continent of the early explorers became the stage for the Ŝnal act in the story of Queen Victoriaıs Empire. In the footsteps of missionaries like David Livingstone, the powers of Europe conducted a brutal race for colonies, a race that would become known as the Scramble for Africa. === Subject: Probability / Combinatorical Problem... Hello... I have 3 counters A, B and C that start at 1. For an experiment X, we deŜne 3 mutually exclusive events eA, eB and eC that occur with probabilities p(eA), p(eB) and p(eC). Each time an event eA occurs, you gain wA1 if A <=4 and wA2 if A = 5, for eB itıs wB1 if B <= 4 and wB2 if B=5, and for eC itıs wC1 if C <= 4 and wC2 if C=5. Then the respective counter is increased by 1 if itıs smaller than 5. If it already had reached 5, it is reset to 1 and the other two counters are set to 5. If you choose to rerun X inŜnitely, what are the expected gains for eA, eB and eC? Well if I only had one counter it would be easy, but how do I deal with those several interacting counters? My Ŝrst idea was to consider a combination of the 3 counters as one state and then solve the problem with Markov chains, but that would lead to a (5^3)*(5^3)-matrix and I donıt think thatıs a clever idea considering that I have a similar problem with much larger counters. Does anyone know which trick is needed for this problem? === Subject: Re: Probability / Combinatorical Problem... >Hello... >I have 3 counters A, B and C that start at 1. For an experiment X, we >deŜne 3 mutually exclusive events eA, eB and eC that occur with >probabilities p(eA), p(eB) and p(eC). >Each time an event eA occurs, you gain wA1 if A <=4 and wA2 if A = 5, >for eB itıs wB1 if B <= 4 and wB2 if B=5, and for eC itıs wC1 if C <= >4 and wC2 if C=5. >Then the respective counter is increased by 1 if itıs smaller than 5. >If it already had reached 5, it is reset to 1 and the other two >counters are set to 5. >If you choose to rerun X inŜnitely, what are the expected gains for >eA, eB and eC? >Well if I only had one counter it would be easy, but how do I deal >with those several interacting counters? My Ŝrst idea was to consider >a combination of the 3 counters as one state and then solve the >problem with Markov chains, but that would lead to a >(5^3)*(5^3)-matrix It leads to a 13 by 13 matrix. Since you are going to rerun X inŜnitely, you do not need to consider the states that are only passed once. > and I donıt think thatıs a clever idea considering >that I have a similar problem with much larger counters. >Does anyone know which trick is needed for this problem? I certainly donıt. :) === Subject: Re: Real Number > There are at least two proofs (both by Cantor) that > show that a 1-1 and onto mapping f:N -> R is not possible, > so thereıs at least two inŜnities (and I believe there are > an inŜnite number of inŜnities, each one constructible > using a power set construction, Sure, there are inŜnitely many cardinals. But what is the cardinality of the set bijectively equivalent inŜnite sets? ;-) Œcid Œooh PS - If someone could answer this, that would be really sweet === Subject: Re: Real Number > > There are at least two proofs (both by Cantor) that > show that a 1-1 and onto mapping f:N -> R is not possible, > so thereıs at least two inŜnities (and I believe there are > an inŜnite number of inŜnities, each one constructible > using a power set construction, > Sure, there are inŜnitely many cardinals. But what is the > cardinality of the set bijectively equivalent inŜnite sets? ;-) > Œcid Œooh > PS - If someone could answer this, that would be really sweet Depending on your axioms this would not be a set but rather a proper class. To see this, weıll show that the collection of all sets of cardinality 2 is in 1 - 1 corrrespondence with the collection of all sets. Let E be the empty set and S be any set. The ordered pair (E, S) or in other symbols, {E, {E, S}} has cardinality 2 and there is one unique such set for every set S. === Subject: Re: Real Number >> There are at least two proofs (both by Cantor) that >> show that a 1-1 and onto mapping f:N -> R is not possible, >> so thereıs at least two inŜnities (and I believe there are >> an inŜnite number of inŜnities, each one constructible >> using a power set construction, > Sure, there are inŜnitely many cardinals. But what is the > cardinality of the set bijectively equivalent inŜnite sets? ;-) There is no such set (as I suspect you are aware), but that each one constructibele using a power set construction part is equivalent to the generalized continuum hypothesis. > Œcid Œooh > PS - If someone could answer this, that would be really sweet Not even a little acidic? -- Dave Seaman Judge Yohnıs mistakes revealed in Mumia Abu-Jamal ruling. === Subject: Re: Irreducible polynomials over Q >> Iıve asked Mathematica to factor (over Q) the polynomial >> x^{24} - x^{12} + 1 and the answer was that itıs irreducible. >> Why? Itıs the 72nd cyclotomic polynomial. > The cyclotomic polynomials are irreducible. Of course they are! > And no, I donıt know how to prove it. Youıll Ŝnd it in nearly every book that deals with Galois theory. See, for instance, Jacobsonıs Basic ALgebra, vol. I. Jose Carlos Santos === Subject: Re: Peanoıs space-Ŝlling curve message >> >> t = 0.d1d2d3d4... >> >> (for example 1/2 = 0.5000..., 1/3 = 0.333..., etc.) >> If t is as above then deŜne x and y by taking the >> odd-numbered digits of t and the even-numbered >> digits of t: >I had considered a procedure similar to this, but rejected >it out-of-hand because it seems to hinge on the axiom of >choice. > This has nothing whatever to do with the axiom of choice. Then one of us has absolutely no idea what the axiom of choice is. You may choose to identify this person as me, because I view your function above as a selection function. >By the way, I donıt recall I actually said >impossible - very remiss of me if I did and I accept a slap >on the wrist. Can you, in your turn point out why? ;-) > Point out why _what_? Are you being deliberately obtuse? I accept a slap on the wrist because I am a scientist and therefore forbidden to use the word impossible. < big snip> > The last three paragraphs are nothing but pompous > nonsense. (Nonsense because nothing that anyone > has said in this thread has anything whatever to do > with the axiom of choice, and pompous because > youıre trying to sound erudite regarding matters > you evidently donıt understand one bit.) Now your not even being obtuse - just downright rude. If you read more carefully I am being the opposite of erudite, trying to elicit your aid by letting you know that I have some slight but passing acquaintanceship with relevant ideas so that you may post without feeling the need to go back to square one. I also felt you might respond to a little humour. It appears I was wrong - tant pis pour toi. Try to lighten up a little, as you Americans say. Re: my nonsense. The contention is that you are using a choice function to map complex numbers into the reals. Obviously you think otherwise, so be so kind as to address that speciŜc point in words I can understand, or else let somebody else do so. > John === Subject: Re: Peanoıs space-Ŝlling curve >> >message >> >>> > > t = 0.d1d2d3d4... > > (for example 1/2 = 0.5000..., 1/3 = 0.333..., etc.) > If t is as above then deŜne x and y by taking the > odd-numbered digits of t and the even-numbered > digits of t: >> >>I had considered a procedure similar to this, but >rejected >>it out-of-hand because it seems to hinge on the axiom of >>choice. >> This has nothing whatever to do with the axiom of choice. >Then one of us has absolutely no idea what the axiom of >choice is. Thatıs very clear. >You may choose to identify this person as me, >because I view your function above as a selection function. Itıs not a question of _identifying_ that person, that person _is_ you. Can you even _state_ the axiom of choice precisely? >>By the way, I donıt recall I actually said >>impossible - very remiss of me if I did and I accept a >slap >>on the wrist. Can you, in your turn point out why? ;-) >> Point out why _what_? >Are you being deliberately obtuse? I accept a slap on the >wrist because I am a scientist and therefore forbidden to >use the word impossible. >< big snip> >> The last three paragraphs are nothing but pompous >> nonsense. (Nonsense because nothing that anyone >> has said in this thread has anything whatever to do >> with the axiom of choice, and pompous because >> youıre trying to sound erudite regarding matters >> you evidently donıt understand one bit.) >Now your not even being obtuse - just downright rude. If you >read more carefully I am being the opposite of erudite, >trying to elicit your aid by letting you know that I have >some slight but passing acquaintanceship with relevant >ideas But itıs clear that (at least when youıre talking about AC) you have _no_ acquaintance with the relevant ideas! You have acquaintance with the _words_. >so that you may post without feeling the need to go >back to square one. I also felt you might respond to a >little humour. It appears I was wrong - tant pis pour toi. >Try to lighten up a little, as you Americans say. >Re: my nonsense. The contention is that you are using a >choice function to map complex numbers into the reals. You have no idea what the phrase choice function means. By what seems to be your interpretation of the axiom of choice, if I deŜne f(x) = 2x I must be using the axiom of choice, because Iım choosing to map x to 2x. (My _guess_ would be that if someone asked you whether the deŜnition f(x) = 2x requires AC youıd answer no. If so then Iım at a loss to explain why you think the deŜnitions above _do_ require AC; those deŜnitions are no more problematic than the deŜnition f(x) = 2x, theyıre just a little more complicated.) >Obviously you think otherwise, so be so kind as to address >that speciŜc point in words I can understand, or else let >somebody else do so. AC says this: Suppose that A is a set and each element of A is a nonempty set. Let S be the union of the elements of A. Then there exists a function f : A -> S such that f(x) is an element of x for every x in A. This gets used in proving that various things exist even though we canıt give explicit constructions of them. All the functions mentioned above (where above refers to the entire thread) are deŜned _explicitly_; no AC involved anywhere. >> >John ************************ David C. Ullrich === Subject: Re: Peanoıs space-Ŝlling curve > t = 0.d1d2d3d4... > > (for example 1/2 = 0.5000..., 1/3 = 0.333..., etc.) > If t is as above then deŜne x and y by taking the > odd-numbered digits of t and the even-numbered > digits of t: >> >>I had considered a procedure similar to this, but > rejected >>it out-of-hand because it seems to hinge on the axiom of >>choice. >> This has nothing whatever to do with the axiom of choice. > Then one of us has absolutely no idea what the axiom of > choice is. You may choose to identify this person as me, > because I view your function above as a selection function. I also identify that person as you. David C. Ullrich *deŜned* a function explicitly; he didnıt just say that by the axiom of choice, thereıs a selection function such that.... If you want to learn what the axiom of choice says, read http://en.wikipedia.org/wiki/Axiom_of_choice >>By the way, I donıt recall I actually said >>impossible - very remiss of me if I did and I accept a > slap >>on the wrist. Can you, in your turn point out why? ;-) >> Point out why _what_? > Are you being deliberately obtuse? I accept a slap on the > wrist because I am a scientist and therefore forbidden to > use the word impossible. Then we mathematicians are not scientists, because we prove that the certain things are impossible (such as squaring the circle with ruler and compass alone) all the time. Jose Carlos Santos === Subject: Re: Peanoıs space-Ŝlling curve message > But this is sufŜcient to show that a bijection exists between the unit > interval and the unit square. Thatıs because of the Cantor-Bernstein > theorem, which says that if you have two sets A and B, each of which can > be injected into the other, then a bijection exists. In the case of the > interval and the square, the bijection cannot be continuous, however. being cast over my darkness, at last! John === Subject: Re: Peanoıs space-Ŝlling curve >> John Morgan >> >> >message >. Semantically speaking, I was >showing up my ignorance - only those who are pig-ignorant >like to show off their ignorance and I donıt think either >of us Ŝt into that category ;-)) > If you donıt _like_ to show off your ignorance then > you _really_ need to stop making comments about all > this and stick exclusively to asking questions. Honest - > I canıt think of anything youıve said in this thread > thatıs actually been correct. I have no problem about being ignorant and will ignore the obvious insult implied above when you use show off instead of show up immediately after I explained the difference to you. But question and answer is not much fun. Still, if it was good enough for Socrates... You must be using the word Honest in an American rather than an English sense of the word. Maybe politics is your calling, that is when you get tired of mathematics or too old for it like me :-) N.b. In case you donıt understand, thatıs a winking smiley at the end, which is intended to show that I am not being too serious in my sarcasm. >> trying to be helpful, which is not the same as trying to >be nice. >Have you ever considered trying to do both at the same time. >Iım told itıs possible though I havenıt seen a proof > It can be very difŜcult when youıre dealing with someone > who clearly understands _nothing_ about the things > heıs talking about, but who doesnıt let that stop him from > repeatedly pointing out why various statements must > be wrong. (Statements the _proofs_ of which are very > well understood by advanced undergraduates whoıve > actually studied the Ŝeld.) Firstly, I have certainly questioned why certain statements vis-a-vis space-Ŝlling are considered to be correct. But nowhere have I said that statements made by you or any other mathy were wrong. I would never presume to do so. I have however, perhaps naively, allowed my thoughts to ŝow too quickly from brain to keyboard. Secondly, I think I_understand_my religious beliefs as well as any undergraduate would. Does that make them true for everybody. If so, why arenıt you all Satanists like me? ;-) N.b.Hope youıve remembered what the winking smiley means ;-) Finally, as Iıve said elsewhere, it wouldnıt hurt you to lighten up a bit. I used to think mathematics was quite a fun thing, and good exercise for my brain. Then I started posting to sci.math and am beginning to doubt it :-( N.b.Thatıs the opposite of a smiley by the way and signiŜes that I am not laughing. Pity really, just when I was beginning to get a handle on some of this stuff. John === Subject: Re: Peanoıs space-Ŝlling curve in >> whether the curve construct described by Peano that >> claims to Ŝll a square, does actually do so. >> >> There is a simple example of how a discrete process (if >inŜnitely applied)can produce a continuous result. Take the >inŜnite series 1/2 + 1/4 + 1/8 + ...+ 1/2^n + ...= 1 >> This series represented as points on a straight line means >that for >> reaching the point of abscissa 1 it must run over >continuous points. >> The Peano Curve follows this same pattern but in two >dimensions. non-mathy. >Unfortunately I canıt seem to reconcile what you are telling >me here with what I thought I knew before! >SpeciŜcally, the approach to the limiting point of this >sum would appear denser and denser when represented as a >graph of the partial sums. Each partial sum can be put into >a one-to-one correspondence with an integer so it seems that >the graph is a geometrical representation of the Aleph_0 >set. The idea you have offered me suggests that the partial >sums form a continuum at the limiting point and so become >Aleph_1. Now Aleph_1 + a Ŝnite or countably inŜnite >number of partial sums equals Aleph_1: a contradiction to >the Ŝrst observation. > Youıre not making _any_ sense. > You mentioned the word biology recently. What youıre > saying here is like if I said that the DNA spiders the > natural chain polymerase selection, leading to > mitochondrial dendrites. At last, something > comprehensible to a non-biologist! Of course > this contradicts the fact that the gene expresses > microtubules. There are grammatical usages that I donıt understand viz. the verb spider. There are semantic juxtapositions that I donıt immediately recognise because of my next point. This is not my area of biology. Iım a gamekeeper turned poacher - an erstwhile chemist who latterly became an ecologist. If it were my Ŝeld perhaps I could point out the semantic difŜculties, or offer suggestions in plain language as to what I think it is you want to say. To be fair, this is what you have tried to do for me, and I would not want you to think for one minute that I am not grateful - I am. But I need time to assimilate all of it, because of the contradictions that I Ŝnd and my inability to dump all my previous knowledge as you suggest in another post on this subject. Quite simply, I believe it is ultimately possible to reconcile my previous understanding with some of what I have already learned here. For example, you recently told me that aleph_1 was not the same cardinality as the power set of aleph_0. I have tried to discard all ideas that I misconceived by believing that they were. Now Iım trying to understand which of these two has the higher cardinality and why,if indeed higher has any meaning. In fact I think I need to read a modern primer. Can you recommend one? John === Subject: Re: Peanoıs space-Ŝlling curve message >> > if he has any sense he pays > no attention to his queasy feelings and tries to > understand what theyıre talking about. Maybe you should become a counsellor for President Dubıyah. > (Which means we must never question the > experts? Absolutely not. But we need to > _understand_ what theyıre saying Ŝrst, before > deciding itıs all wrong.) I havenıt decided any such thing. What I am trying to decide is if what you mathies have discovered about abstract spaces is usable as a model for real space and time. >But then scientists can never, ever know if they >are correct ;-) > Thatıs a big difference between mathematics > and the natural sciences. Because on this side > of the fence we have this thing called _proof_ > (yes, the word exists over there as well, but it > doesnıt mean the same thing.) But it does mean the same thing, and we know that we canıt have it. N.b. I canıt prove that last statement ;-) >> Especially since weıre talking about >> abstract mathematics, and youıve stated repeatedly that >> you donıt _know_ the math. >Iım trying to know the math and you may be pleased to hear >that your posts are helping in this endeavour. But are we >really talking about abstract mathematics here? >I sketched part of the Peano curve and it looked pretty >concrete to me. Perhaps all mathematics is abstract, even >the applied stuff, so shall we just leave out the word >abstract ? > Yes, weıre talking about abstract mathematics. No, > you have _not_ sketched that curve! You have > sketched _other_ curves which form _approximations_ > to that curve. Which gets right back to the nub of my problem. I draw a bit of the construction and then imagine further recursions. I note some points exist that will never be traced by any number of countable recursions. I also Ŝnd points that are included more than once and topology tells me that I no longer have a structure that is homeomorphic with a line (0,1). Any wonder then that I am confused by your assertions that a piece of abstract algebra can be used to show that neither of these concrete discoveries are correct. When you read this you will also need to allow for the fact that I am not able to put a mathspeak spin on it, but that perhaps you should try to understand it nevertheless. Otherwise we can never discuss anything because, as you have so often pointed out, I donıt have the years and years of immersion in this stuff that you have. I am assuming you do want to discuss it as you keep on replying to my posts. > The fact that those approximations actually converge > to _something_ has a lot to do with the fact that the > reals are complete. And the completeness of the > reals is deŜnitely an abstract thing - there is nothing > in the physical world that corresponds precisely to > the real numbers (or if there is thereıs no way we > could possibly know that.) Despite this, the reals can be used as adequate models for a huge range of natural objects. Other objects exist for which we need two real numbers. For some of which, such as areas, we can get away with one real, and a unit that is separately deŜned. Itıs this aspect of the universe that I canıt yet reconcile with Peanoıs construction, wherein a line and an area have a correspondence that allows functions to take us between them. N.b. I am lacking the proper mathspeak here and hope you can Ŝnd the volition to try to understand what I am gibbering about. John === Subject: Re: Peanoıs space-Ŝlling curve >> >message > > >> if he has any sense he pays >> no attention to his queasy feelings and tries to >> understand what theyıre talking about. >Maybe you should become a counsellor for President Dubıyah. >> (Which means we must never question the >> experts? Absolutely not. But we need to >> _understand_ what theyıre saying Ŝrst, before >> deciding itıs all wrong.) >I havenıt decided any such thing. What I am trying to decide >is if what you mathies have discovered about abstract spaces >is usable as a model for real space and time. >>But then scientists can never, ever know if they >>are correct ;-) >> Thatıs a big difference between mathematics >> and the natural sciences. Because on this side >> of the fence we have this thing called _proof_ >> (yes, the word exists over there as well, but it >> doesnıt mean the same thing.) >But it does mean the same thing, and we know that we canıt >have it. N.b. I canıt prove that last statement ;-) > Especially since weıre talking about > abstract mathematics, and youıve stated repeatedly that > you donıt _know_ the math. >> >>Iım trying to know the math and you may be pleased to >hear >>that your posts are helping in this endeavour. But are we >>really talking about abstract mathematics here? >>I sketched part of the Peano curve and it looked pretty >>concrete to me. Perhaps all mathematics is abstract, even >>the applied stuff, so shall we just leave out the word >>abstract ? >> Yes, weıre talking about abstract mathematics. No, >> you have _not_ sketched that curve! You have >> sketched _other_ curves which form _approximations_ >> to that curve. >Which gets right back to the nub of my problem. I draw a bit >of the construction and then imagine further recursions. I >note some points exist that will never be traced by any >number of countable recursions. I also Ŝnd points that are >included more than once and topology tells me that I no >longer have a structure that is homeomorphic with a line >(0,1). Any wonder then that I am confused by your assertions >that a piece of abstract algebra can be used to show that >neither of these concrete discoveries are correct. Nobody has denied either of those facts. In fact both of them were explained to you _many_ times in this thread. Exactly where did I assert what you say Iıve asserted? >When you read this you will also need to allow for the fact >that I am not able to put a mathspeak spin on it, but that >perhaps you should try to understand it nevertheless. Understand _what_? >Otherwise we can never discuss anything because, as you have >so often pointed out, I donıt have the years and years of >immersion in this stuff that you have. I am assuming you do >want to discuss it as you keep on replying to my posts. >> The fact that those approximations actually converge >> to _something_ has a lot to do with the fact that the >> reals are complete. And the completeness of the >> reals is deŜnitely an abstract thing - there is nothing >> in the physical world that corresponds precisely to >> the real numbers (or if there is thereıs no way we >> could possibly know that.) >Despite this, the reals can be used as adequate models for a >huge range of natural objects. That seems to be true, at least if we donıt look at things at a Ŝne enough scale. When we start talking about a very tiny scale itıs not at all clear to physicists what space and time look like - they _could_ be something like the reals, they could instead be discrete/quantized. >Other objects exist for which >we need two real numbers. For some of which, such as areas, >we can get away with one real, and a unit that is separately >deŜned. Itıs this aspect of the universe that I canıt yet >reconcile with Peanoıs construction, wherein a line and an >area have a correspondence that allows functions to take us >between them. N.b. I am lacking the proper mathspeak here >and hope you can Ŝnd the volition to try to understand what >I am gibbering about. >John ************************ David C. Ullrich === Subject: Re: 640,000,000,000 TO 1 >> I have seen this Ŝgure calculated out in a previous >> but basicly if you take ALL the possible DNA options >> and multiply them out you get a Ŝgure that rounds >> down to 640 billion. > Does that mean that there are 640 billion possible human beings, up to > differences in nurture? I presume some are more likely to be generated > than others so it is difŜcult to calculate exactly when the human > genome-space will have been completely Ŝlled, or how long weıre likely to > have to wait before someone is duplicated. But a back-of-the-envelope > calculation shows that if the world population climbed to, say, 12 billion > (projected within the next half-century) and stayed stable there, then > itıs likely that all possible human beings will have been born after two > or three thousand years (if the 640 billion Ŝgure is right). I donıt like > this thought at all! (Even though I believe nurture and environment play > a big role in determining oneıs personhood.) Identical twins have identical genomes but are different people even with similar nurturing and environment. > If you factor in possible harmless mutations over such a period of time > and such a population, to expand the available DNA options, how much is > that likely to affect the 640 billion Ŝgure? Can someone verify my > calculation? Iıd be happier knowing we werenıt about to exhaust our > genetic possibilities within a (geological) eye-blink. There are about 30,000 genes in the human genome with any two reproductively capable people sharing about 94% of their genes so they would be able to produce 2^1800 genetically distinct offspring, not counting mutations and junk DNA variations. 2^1800 is about 10^541. There are an estimated 10^80 protons and neutrons in the universe. Create a universe of each proton and neutron and a universe of each of those protons and neutrons to about 6 iterations and that is how many different children could be produced by any two people. Then consider how much variation there is in the population of the human race. -- Greg G. A successful acupuncture is a jab well done. === Subject: Re: 640,000,000,000 TO 1 > I have seen this Ŝgure calculated out in a previous > but basicly if you take ALL the possible DNA options > and multiply them out you get a Ŝgure that rounds > down to 640 billion. > Does that mean that there are 640 billion possible human beings, up > to > differences in nurture? I presume some are more likely to be > generated > than others so it is difŜcult to calculate exactly when the human > genome-space will have been completely Ŝlled, or how long weıre > likely to have to wait before someone is duplicated. But a > back-of-the-envelope calculation shows that if the world population > climbed to, say, 12 billion (projected within the next half-century) > and stayed stable there, then itıs likely that all possible human > beings will have been born after two or three thousand years (if the > 640 billion Ŝgure is right). I donıt like this thought at all! > (Even > though I believe nurture and environment play a big role in > determining oneıs personhood.) > If you factor in possible harmless mutations over such a period of > time and such a population, to expand the available DNA options, how > much is that likely to affect the 640 billion Ŝgure? Can someone > verify my calculation? Iıd be happier knowing we werenıt about to > exhaust our genetic possibilities within a (geological) eye-blink. > What is the problem if there is duplication? What do you expect to > happen if there is a man identical to a previous man or a snowŝake > identical to a previous snowŝake? I canıt imagine the universe would > come to an end or the concept of human rights ceases to have any sway > over the minds of men. We can cope with twins and triplets so I see no > reason why we should be freaked out by identical strangers of > different ages. > -- > Martin Willett > http://mwillett.org/ Its not like coming up with the 9,000,000 names of god is it? -- apatriot #23, aa #1779, Grand Pubba, EAC Department of Oxygen Deprivation Gary Bohn Conservatism is not about tradition and morality, hasnıt been for many decades...It is about the putative biological and spiritual superiority of the wealthy. Greg Bear === Subject: Re: 640,000,000,000 TO 1 > Conservatism is not about tradition and morality, hasnıt been for many > decades...It is about the putative biological and spiritual superiority of > the wealthy. > Greg Bear And wealth is a heritable trait. More heritable than intelligence, height, eye color, shoe size ... -- TP === Subject: Re: 640,000,000,000 TO 1 >Its not like coming up with the 9,000,000 names of god is it? Noooooo! Not that! Anything but that! The peace of God be with you. Stanley Friesen === Subject: Re: How to read partial differentials when reading aloud...? so how do you say r (dr) r ? arrrgghhhh, matey. > Hello all, > I canıt Ŝnd this information in an FAQs or textbooks. > I know that when you are reading out an equation or such, > you usually read the derivative of x with respect > to y (dx/dy) in itıs shortened form dee-ex-dee-why. > But how do you read the partial derivative of x with respect > to y? Is it still just dee-ex-dee-why as long as the context > is set that youıre working with partial differentials? > Yes, and if the context is hostile, you can say > partial-dee-ex-dee-why > Also, what about the second partial derivative of x with respect > to y? > I have heard one of my colleague students read it as > deedee-ex-dee-why-why, > but I wonder whether he would have said > deedee-ex-dee-tee-tee > for derivatives w.r.t. time ;-) > I always read (or Œthinkı) it as > dee-second-ex-[over]-dee-why-squared > or, whem Iım lazy, simply as > dee-second-ex-dee-why > and if necessasy I would add the partial preŜx. > If there is some sort of resource that tells you how to read > these? > I think this is it :-) > hth > Dirk Vdm === Subject: Re: How to read partial differentials when reading aloud...? >so how do you say r (dr) r ? Very amusing. -- Stephen J. Herschkorn herschko@rutcor.rutgers.edu === Subject: Re: How to read partial differentials when reading aloud...? > so how do you say r (dr) r ? > arrrgghhhh, matey. I have never seen or written an expression even remotely like r (dr) r but it would sound like a bitch indeed ;-) Give me 2 to Duluth please? Dirk Vdm === Subject: Re: How to read partial differentials when reading aloud...? It is a commuted form of d(r^3/3). > so how do you say r (dr) r ? > arrrgghhhh, matey. > I have never seen or written an expression even > remotely like > r (dr) r > but it would sound like a bitch indeed ;-) > Give me 2 to Duluth please? > Dirk Vdm === Subject: Re: How to read partial differentials when reading aloud...? > .... > I know that when you are reading out an equation or such, > you usually read the derivative of x with respect > to y (dx/dy) in itıs shortened form dee-ex-dee-why. > But how do you read the partial derivative of x with respect > to y? Is it still just dee-ex-dee-why as long as the context > is set that youıre working with partial differentials?.... Curiously enough, the same question came up last month on the little news group alt.math under the title What is it called? Hereıs what I posted there. > As youıve probably realized from other replies, thereıs no > standard name for it. A very careful reading of y/x is partial d y > by d x. When I was a student, the local physicists gave some thought > to a good short name, and came up with dir (rhyming with sir, but > without sounding the r). I Ŝnd it quite convenient to say dir y by > dir x, but of course itıs not standard. > Thereıs a similar problem with the Jacobi elliptic functions > sn(u), cn(u), dn(u), sc(u), etc. (12 of them altogether, using any > ordered pair of the letters s, c, d, n). Iıve thought about a handy > vowel to pronounce in the middle of those, without producing any uncouth > words. :-) My choice is the AW sound, so for example I pronounce > dn(u) as dawn u. But of course thatıs not standard either. > Ken Pledger. === Subject: Re: Help Needed Understanding Article >2. I proved that the NOT rule is valid and made comments about how the >other rules can be similarly proven valid. >>No, you stated the program transformation rule for the NOT rule. Now you >>have to prove that it is valid. > That is not true. I already did that. What is wrong with my proof? > Quote what is wrong. Do you want me to copy it here again? There is something that looks like a proof of the validity of the NOT rule. Granted. It is the most trivial rule to prove correct. Please provide proof for the other rules as well. (You wonıt get away with stating that they go in the same way.) >>Yes, I know other people have done that >>already. Refer to their paper, because you are building on their work. > Those theorems were developed 10 years before computers were invented. So what? > And, as I said, the fact that I am also able to synthesize theorems > from the Theory of Computation does not mean that they did anything > that I used. Yes, you did. You used *their* result that the rules are valid. > It means I have a fantastic system with lots of > functionality that nobody else has ever done before. No, you have no system at all. You admitted that already. And you donıt have a theoretical description of a system either, because you donıt prove anything about it (except validity of the NOT rule, which is trivial and not your contribution). >>(And similarly for the other rules: either prove them valid yourself or >>refer to the work of others for the proof.) > What is wrong with the proof that I gave? (I see no point in copying > it into a message again, unless you insist.) You only gave a proof for the NOT rule. You also must prove it for the other rules. And you must prove that the programs you gave for your axioms are correct. Note that in order to prove this, you also need some sort of formal semantics for your programming language, which you donıt have. You may consider to use some well-investigated, theoretical, Turing-Complete programming language like WHILE. (But then you have to give credit to others of course, which you seem to dislike very much.) I donıt say these proofs are difŜcult. Only that I donıt see them in your paper. And that they are required. >3. I gave 2 explicit examples, in complete detail, of how programs are >synthesized: a program to determine if one number is a factor of >another, and a program to list all prime numbers between any two given >numbers. >>Yes, you gave *examples*. Which are not even very convincing, because >>for each example you add new axioms to obtain your result. > Not true. Substantiate. every time you notice that your 8 *universal* rules of inference donıt sufŜce anymore? [snip question I already answered] [snip question I already answered] [snip question I already answered] (Sorry, I have a job to do. I am not going to repeat myself every time.) >Those are just non sequiturs. >>I donıt see any thus or therefore in my text. Where is the non sequitur? > The sequence of sentences. There are no sequiturs in the text. There are a number of points that do not follow from each other, followed by a *question* (which doesnıt follow from something by deŜnition). Do you know what non sequitur means, or did you just want to write something in latin in order to appear intelligent? >>I snipped a proof that the program enumerates the natural numbers, yes. >>(First you deŜne P to be the natural numbers, > No I did not. Yes, you did. You deŜned P to be a set which contains 0, and of each element of P its successor. These are the natural numbers. >>then you prove that the >>program outputs every element of P.) So there are two problems with your >>proof: >>* It is not a derivation in your logic, but a proof. > Yes, it is a proof of Induction from my axiom TRUE(x) as you asked. You claimed TRUE(x) where equivalent to Peanoıs axioms. So in particular, it implies induction. You have to give a derivation of induction from assumption TRUE(x). You didnıt give that. > No, it doesnıt use my rules of inference, as they are for Program > Synthesis. Those are two separate functions. Indeed. This was precisely the point I tried to make by asking you to provide a derivation. *You* claimed however they were equivalent. >>* It does not derive the desired result. > What is wrong with it? The above is not true. Substantiate. Enumerating the natural numbers, is something different than induction. >>It is relevent because you obviously donıt know what youıre talking >>about. In the above, the NOT rule is not a rule but an axiom. Adding an >>axiom P->Q to a system is *not* equivalent to adding a rule P=>Q. You >>should not confuse the two. > You can call it anything you want, but it works great, as I have > shown. As I have pointed out, it is very important how you call things. If you call it axioms you can prove more things than if you call it rules. There are two cases: * They are really axioms, but you call them rules. But then, according to *your own* system, you canıt use transformation rules as these axioms are applied, but you have to give programs for these axioms. Since you give transformation rules rather than programs, the conclusion is, in this case, that you donıt know what youıre talking about. * They are really rules of inference. But then your claim that you apply rules of inference by applying other rules of inference (substitution and modes ponens), makes no sense. (Think about it, in order to apply the substition rule, you have to use the substitution rule.) So, also in this case, the conclusion is that you donıt know what youıre talking about. Therefore: you donıt know what youıre talking about. QED. You have no idea what your own system can do. It is not a formal system at all, but an inelegant, informal hack, using ad-hoc axioms. groente -- Sander === Subject: Improper integral Let t>-1 . f(x)=log(x) * x^t Show that the integral of on [0,1] exists. ( Donıt use imtegraion by part) === Subject: Re: Improper integral Select k such that t < k < -1. Compare the given integrand with (-)t^k. --OL === Subject: Re: Improper integral >Let t>-1 . f(x)=log(x) * x^t >Show that the integral of on [0,1] exists. >( Donıt use imtegraion by part) Well what _are_ you allowed to use? Hereıs a hint towards a solution, donıt know whether itıs legal: Choose r so t > r > -1. Then t = r + s, where r > -1 and s > 0. Write log(x) * x^t = (log(x) * x^s) * x^r. Think about how log(x) * x^s and x^r behave... ************************ David C. Ullrich === Subject: Re: Improper integral > Let t>-1 . f(x)=log(x) * x^t > Show that the integral of on [0,1] exists. > ( Donıt use imtegraion by part) Integral of ?? Let t = 0. Looks very inproper. === Subject: Re: Improper integral William Elliot escribi.97: >> Let t>-1 . f(x)=log(x) * x^t >> Show that the integral of on [0,1] exists. >> ( Donıt use imtegraion by part) > Integral of ?? > Let t = 0. Looks very inproper. Int(ln(x), x, r, 1) = (1ln(1) - 1) - (r*ln(r) - r) = r - r*ln(r) - 1 And Lim( r - r*ln(r) - 1, r, 0+) = -1 Because Lim(r*ln(r), r, 0+) = Lim(ln(r)/(1/r), r, 0+) = Lim((1/r)/(-1/r^2), r, 0+) = Lim(-r, r, 0+) = 0 -- Ignacio Larrosa Ca.96estro A Coru.96a (Espa.96a) ilarrosaQUITARMAYUSCULAS@mundo-r.com === Subject: Re: Improper integral > Let t>-1 . f(x)=log(x) * x^t > Show that the integral of on [0,1] exists. > ( Donıt use imtegraion by part) There is a h in [0,1], f is integrable on [h,1] and for any x in ]0,h], |ln(x)|<=1/x^[(t+1)/2], |f(x)|<=x^[(t-1)/2] which is integrable on [0,h]. -- Julien Santini === Subject: Need help calculating the norm of a linear operator Let (F_n) be a sequence of linear operators L2 -> R, = int_{t=-1..1}x(t)*cos(pi*n*t)dt. I need to show that (F_n) does not converge to 0 operator. There is a hint that it is provable that ||F_n|| = 1 for all n. Actually proving the original statement seems easier for me than proving the hint. For every F_n thereıs an obvious x_n from L2 such that ||x_n||=1 and x_n(t)*cos(pi*n*t) = |cos(pi*n*t)|, so int_{t=-1..1}x(t)*cos(pi*n*t)dt = 2/pi and sup_{||x||=1}= 2/pi. It is also easy to show that ||F_n|| is upper bounded by 1+1/2 using the fact that |cos(pi*n*t)| <= 1. But how === Subject: Re: Need help calculating the norm of a linear operator >Let (F_n) be a sequence of linear operators L2 -> R, = >int_{t=-1..1}x(t)*cos(pi*n*t)dt. I need to show that (F_n) does not >converge to 0 operator. There is a hint that it is provable that >||F_n|| = 1 for all n. Actually proving the original statement seems >easier for me than proving the hint. For every F_n thereıs an obvious >x_n from L2 such that ||x_n||=1 and x_n(t)*cos(pi*n*t) = >|cos(pi*n*t)|, so int_{t=-1..1}x(t)*cos(pi*n*t)dt = 2/pi and >sup_{||x||=1}= 2/pi. It is also easy to show that ||F_n|| is >upper bounded by 1+1/2 using the fact that |cos(pi*n*t)| <= 1. But how Somewhere in the book youıll Ŝnd a thing called the Schwarz inequality, or the Cauchy-Schwarz inequality (together with a statement of when equality holds.) ************************ David C. Ullrich === Subject: Re: Need help calculating the norm of a linear operator >>Let (F_n) be a sequence of linear operators L2 -> R, = >>int_{t=-1..1}x(t)*cos(pi*n*t)dt. I need to show that (F_n) does not >>converge to 0 operator. There is a hint that it is provable that >>||F_n|| = 1 for all n. Actually proving the original statement seems >>easier for me than proving the hint. For every F_n thereıs an obvious >>x_n from L2 such that ||x_n||=1 and x_n(t)*cos(pi*n*t) = >>|cos(pi*n*t)|, so int_{t=-1..1}x(t)*cos(pi*n*t)dt = 2/pi and >>sup_{||x||=1}= 2/pi. It is also easy to show that ||F_n|| is >>upper bounded by 1+1/2 using the fact that |cos(pi*n*t)| <= 1. But how >Somewhere in the book youıll Ŝnd a thing called the Schwarz >inequality, or the Cauchy-Schwarz inequality (together with >a statement of when equality holds.) Given that Alexander Korovyev is posting from .ru, he might also want to search for (some version, possibly in Cyrillic) of Bunyakovski, as well. Lee Rudolph === Subject: Re: Need help calculating the norm of a linear operator >Let (F_n) be a sequence of linear operators L2 -> R, = >int_{t=-1..1}x(t)*cos(pi*n*t)dt. I need to show that (F_n) does not >converge to 0 operator. There is a hint that it is provable that >||F_n|| = 1 for all n. Actually proving the original statement seems >easier for me than proving the hint. For every F_n thereıs an obvious >x_n from L2 such that ||x_n||=1 and x_n(t)*cos(pi*n*t) = >|cos(pi*n*t)|, so int_{t=-1..1}x(t)*cos(pi*n*t)dt = 2/pi and >sup_{||x||=1}= 2/pi. It is also easy to show that ||F_n|| is >upper bounded by 1+1/2 using the fact that |cos(pi*n*t)| <= 1. But how >>Somewhere in the book youıll Ŝnd a thing called the Schwarz >>inequality, or the Cauchy-Schwarz inequality (together with >>a statement of when equality holds.) >Given that Alexander Korovyev is posting from .ru, he might also >want to search for (some version, possibly in Cyrillic) of >Bunyakovski, as well. (In fact I even realized why it might be relevant here...) >Lee Rudolph ************************ David C. Ullrich === Subject: Multiplication of negative binary numbers. Gıday Gıday Folks, Twoıs complement works Ŝne for producing functional positive and negative numbers so long as we conŜne ourselves to addition. Twoıs complement sometimes give the right answer with subtraction and sometimes doesnıt. 0011 3 -1001 -(-7) = 1010 = 10 works, 0111 7 -1001 -(-7) = 1110 = -2 doesnıt. Is there a binary code that can deal with (negative number)*(negative number) = positive number? Twoıs complement obviously doesnıt. Here is a 4-bit example. 1001 x1110 = 0000 + 1 0010 + 10 0100 + 100 1000 It doesnıt seem to matter if we include the overŝow or not. In this instance the msb is 1 whatever we choose to do. Best wishes, -- Quentin Grady ^ ^ / New Zealand, >#,#< [ / / ... and the blind dog was leading. http://homepages.paradise.net.nz/quentin === Subject: Re: Multiplication of negative binary numbers. !3KEIp?*w`|bL5qr,H)LFO6Q=qx~iH4DN;i;/yuIsqbLLCh/!U#X[S~( 5eZ41to5f%E@ıELIi $t^ VcLWP@J5p^rst0+(Œ>Er0=^1{]M9!p?&:z]|;&=NP3AhB!B_bi^]Pfkw > Gıday Gıday Folks, > Twoıs complement works Ŝne for producing functional positive and > negative numbers so long as we conŜne ourselves to addition. > Twoıs complement sometimes give the right answer with subtraction and > sometimes doesnıt. It gives the right answer if the right answer is representable. The right answer is representable if the carry into the MSB has the same sign as the carry out of the MSB. > 0011 3 > -1001 -(-7) > = 1010 = 10 works, > 0111 7 > -1001 -(-7) > = 1110 = -2 doesnıt. > Is there a binary code that can deal with > (negative number)*(negative number) = positive number? > Twoıs complement obviously doesnıt. Here is a 4-bit example. > 1001 > x1110 > = 0000 > + 1 0010 > + 10 0100 > + 100 1000 > It doesnıt seem to matter if we include the overŝow or not. > In this instance the msb is 1 whatever we choose to do. If one factor is negative, subtract the other factor from the high word of the result. And if the other is negative, do the same the other way round. -- David Kastrup, Kriemhildstr. 15, 44793 Bochum === Subject: Re: Length > > Force does not always cause motion; as such; but will cause > deformation and distortions such as simple compression. > I donıt want you to come to the wrong conclusion, Shead, so > be aware that if a net force acting on a mass is not zero, > ^^^^^^^^^ > that mass is going to accelerate. > Newtonıs Second Law > http://scienceworld.wolfram.com/physics/NewtonsSecondLaw.html That says: ŒA force [F] acting on a body gives it an acceleration [a] which is in the direction of the force and has magnitude inversely proportional to the mass [m] of the bodyı: According to that Earthıs surface which is acted on all around by the force of atmospheric pressure must be accelerating centripetally toward its center. No wonder there are so many goofy theories ŝoating around. The fact is that the force of the atmosphere, is due to its weight, and along with the weight of the ground itself, as well as the weight of the oceans is squeezing Earth from all directions, keeping it compressed together. Any inward motion is so slight as to be unoticable, except perhaps for occasional earthquakes; but the pressure increase with depth is quite well known. === Subject: Re: Length > > Force does not always cause motion; as such; but will cause > deformation and distortions such as simple compression. > I donıt want you to come to the wrong conclusion, Shead, so > be aware that if a net force acting on a mass is not zero, > ^^^^^^^^^ > that mass is going to accelerate. > Newtonıs Second Law > http://scienceworld.wolfram.com/physics/NewtonsSecondLaw.html > That says: ŒA force [F] acting on a body gives it an acceleration [a] > which is in the direction of the force and has magnitude inversely > proportional to the mass [m] of the bodyı: > According to that Earthıs surface which is acted on all around by the > force of atmospheric pressure must be accelerating centripetally > toward its center. No wonder there are so many goofy theories ŝoating > around. The net force on the atmosphere is zero (ignoring the temperature and ^^^^^^^^^ and pressure variations near the surface driven by the Sun and known as weather. You think things are goofy simply because you donıt understand some basic principles of physics. Newtonıs laws are deŜnitely insightful in this instance. === Subject: det(A+B) once more If A and B are 2*2, then det(A+B)=det(A)+det(B) <=> det(A+l*B)=det(A)+det(l*B) for any (nonzero) scalar l. Can this be extended somehow to n*n? (I think yes, except that other certain values than 0 must be excluded.)1 -- Hauke Reddmann <:-EX8 fc3a501@uni-hamburg.de als man ankam wollte man werden, die geschichte schreiben, die doofen sollen sterben, der plan als man damals nach hamburg kam (Kettcar) === Subject: Re: det(A+B) once more >If A and B are 2*2, then >det(A+B)=det(A)+det(B) <=> det(A+l*B)=det(A)+det(l*B) >for any (nonzero) scalar l. >Can this be extended somehow to n*n? >(I think yes, except that other certain values than 0 >must be excluded.) Iıll use t instead of l, which looks too much like 1 in the fonts I use. P(t) = det(A+tB) - det(A) - det(tB) is a polynomial of degree at most n-1 and P(0) = 0. So if it is 0 for n-1 different nonzero values of t, you can conclude it is always 0. Robert Israel israel@math.ubc.ca Department of Mathematics http://www.math.ubc.ca/~israel University of British Columbia Vancouver, BC, Canada V6T 1Z2 === Subject: Relative Measure & Relative Product of Dynamical Systems Does somebody know deŜnitions : Relative Measure and Relative Product of Dynamical Systems... or know where they could be on the net ? M.B. === by support1.mathforum.org (8.11.6/8.11.6/The Math Forum, $Revision: 1.9 primary) id i4PCYEP09572; >Suppose that n is positive integer. Suppose that a and b are positive >real number. >How to simplify/compute the following integral. >Int[0, INFINITE] x^n exp^( - (x-a)^2/ (2b^2)) dx >In this expression, Int[0 , INFINITE] represents the integral from >zero to inŜnite. x is the variable. >-------------- >ZHANG Yan Letıs denote your integral by I(n). Then integration by parts yields the recursion formula I(n)= a*I(n-1)+b^2*(n-1)*I(n-2) for n>=2 along with I(0)= sqrt(pi/2)*b*ERF(a/(sqrt(2)*b)) + sqrt(pi/2)*b I(1)= a*I(0) + b^2*exp(- a^2/(2*b^2)) where ERF(x)= 2/sqrt(pi)*int(-t^2,t,0,x) is the error function. (I have been using the Derive-notation above, but I hope it is self- explanatory nevertheless.) The formula above is already very convenient, if you want to compute I(n) for some speciŜc n>=0. If you are very ambitious though, you could try to go a step further and consider the generating function f(x):= sum(I(n)*x^n,n,0,inf) which obeys a differential equation of order 2 according to the recursion above. Johann === Subject: Re: Questions about groups, inverses, and continuity. by support1.mathforum.org (8.11.6/8.11.6/The Math Forum, $Revision: 1.9 primary) id i4PCYEm09580; >(Hobby mathematician asks...) >Let x be an element of the algebra G(A) over the reals generated from >some Ŝnite group G = {e, g_2, ..., g_n}. >Then >inf {| 1 - |t_1| + |t_2| +...+ |t_n| | : y in G(A), > x*y = (t_1)e + (t_2)g_2 + ... (t_n)g_n } = 0 >is a necessary condition for the existence of x^{-1}. >Questions >1. Is the condition also sufŜcient? >2. Norm G(A) by setting, for example, > ||x|| = || (x_1)e + ... (x_n)g_n || = |x_1| + ... + |x_n|. > > DeŜne the function f:G(A) -> R^{+}, > f(x) = inf {| 1 - |t_1| + |t_2| +...+ |t_n| | : y in G(A), > x*y = (t_1)e + (t_2)g_2 + ... (t_n)g_n } > Under what possible conditions on G(A) is f continuous at... > (a) points xı such that f(xı) = 0 > (b) every point ? >C. Dement I should have checked http://mathworld.wolfram.com/GroupAlgebra.html Ŝrst. It gives some helpful hints on notation, but does not appear to mention that the basis vectors {e, g_2, ..., g_n} must be linear independent- which I had implicitely assumed without even mentioning it. I know this to be true for Ŝnite abelian groups (see Mackey, for ex.: Unitary Group Representations), as the one dim. character table of such a group is nothing more than a collection of orthogonal row vectors. I am not sure how to prove the general case, however. C. Dement === Subject: Real analyses- measurable sets.... Help urgently needed No matter how I start, I always end up with the same and Iıd really appreciate some help on this...... (I hope u can understand the problem, as I translate it to English and I donıt learn Math in English....) Prove that for given E>0, there exists a subset A of R (set of real numbers) with these characteristics: 1. for every x from R, there exists a surroundings of x such that no element from A is in that surroundings 2. A is measurable 3. Lebesgueıs measure of A is Prove that for given E>0, there exists a subset A of R (set of real > numbers) with these characteristics: > 1. for every x from R, there exists a surroundings of x such that no > element from A is in that surroundings What do you call a surrounding ? If itıs a neighbourhood, then only the empty set would do. > 2. A is measurable > 3. Lebesgueıs measure of A is No matter how I start, I always end up with the same and Iıd really > appreciate some help on this...... > (I hope u can understand the problem, as I translate it to English and > I donıt learn Math in English....) > Prove that for given E>0, there exists a subset A of R (set of real > numbers) with these characteristics: > 1. for every x from R, there exists a surroundings of x such that no > element from A is in that surroundings > 2. A is measurable > 3. Lebesgueıs measure of A is Any help in summing the following series would be welcomed! > 4 pi (-1)^k >sum_{k = 1}^{infty } = ------------------------ > -1 + exp(pi*(2k+1)) >If youıre wondering it is the the integral over R of the error in the >Sinc Cardinal Series for Sech. -0.00101229164605 using matlab an easy exercise, since this is a rapidly converging alternating series, no problems hth peter === Subject: Entropy of samples on real line segment. Is there a precise measure/deŜnition of the Œentropyı of N points on the real line segment [0,1]? I am guessing that N points positioned at (i+.5)/N (where i=0...N-1) gives the conŜguration with Œmaximumı entropy. Sabbir. === Subject: False proofs of FLT Hi! Could you point me to a good source of interesting and short false proofs of FLT to check my personal-probably-wrong-too-short-and-simple-proof of FLT? TIA. N. === Subject: Re: False proofs of FLT > Hi! > Could you point me to a good source of interesting and short false proofs of > FLT to check my personal-probably-wrong-too-short-and-simple-proof of FLT? > TIA. > N. Just post it and somebody will tell you whatıs wrong with it. If you post it while being extremely arrogant, condescending, and insulting, then 20 people will tell you whatıs wrong with it, in great detail. That probably wonıt help you any more than the other, but itıs funny to watch. Nathan === Subject: Re: False proofs of FLT > Hi! > Could you point me to a good source of interesting and short false proofs of > FLT to check my personal-probably-wrong-too-short-and-simple-proof of FLT? > TIA. > N. > Just post it and somebody will tell you whatıs wrong with it. If you > post it while being extremely arrogant, condescending, and insulting, > then 20 people will tell you whatıs wrong with it, in great detail. > That probably wonıt help you any more than the other, but itıs funny > to watch. :-)) Dirk Vdm === Subject: Re: False proofs of FLT > Could you point me to a good source of interesting and short false proofs of > FLT to check my personal-probably-wrong-too-short-and-simple-proof of FLT? Isnıt it easier to just post your attempt? Short, false proofs often apply to the case p = 2 also, so you may want to check that Ŝrst. -- J K Haugland http://www.neutreeko.com === Subject: Re: False proofs of FLT Yes, but I dont want to look like a crank. I prefer to check if I made some common mistake Ŝrst ;) > Could you point me to a good source of interesting and short false proofs of > FLT to check my personal-probably-wrong-too-short-and-simple-proof of FLT? > Isnıt it easier to just post your attempt? Short, false proofs often > apply to the case p = 2 also, so you may want to check that Ŝrst. > -- > J K Haugland > http://www.neutreeko.com === Subject: Re: False proofs of FLT days. My association with the Department is that of an alumnus. >Yes, but I dont want to look like a crank. You might want to stop top-posting as a Ŝrst step... (that refers to the practice of replying to a post by writing all new material Ŝrst, on top, and then quoting the message you are replying to). Many people Ŝnd it annoying, and it is hard to read; particularly if and when you post an argument and want to ask questions, it makes more sense to intersperse your comments with what you are addressing. > I prefer to check if I made some common mistake Ŝrst ;) So go through it. If you cannot Ŝnd an error, then you may post it saying that you cannot Ŝnd and error and would welcome comments; simply saying I have this argument and cannot see anything wrong with it... doesnıt make you look like a crank. Posting it and claiming it is the best thing since sliced bread and that nobody can possibly Ŝnd anything wrong with it would; your reactions to criticisms or questions may also label you as a crank, but the simple act of posting and asking questions will not. But the suggestion you got already is a good one: run through your argument with n=2 (n being the exponent). If you can see no problem with the argument when n is 2, then there is certainly something wrong, with your perception and your argument (since there are many integer solutions to a^2+b^2=c^2). That would give you a clue as to whether your ability to spot errors is good enough, and whether your argument passes the most standard of crank-detecting tests. -- Itıs not denial. Iım just very selective about what I accept as reality. --- Calvin (Calvin and Hobbes) Arturo Magidin magidin@math.berkeley.edu === Subject: Re: False proofs of FLT > Hi! > Could you point me to a good source of interesting and short false proofs of > FLT to check my personal-probably-wrong-too-short-and-simple-proof of FLT? Underwood Dudley has a book on cranks. I believe one chapter is on FLT. === Subject: Re: False proofs of FLT Unfortunately Im from spain I cant have access to such books. I was looking for a web site. > Hi! > Could you point me to a good source of interesting and short false proofs of > FLT to check my personal-probably-wrong-too-short-and-simple-proof of FLT? > Underwood Dudley has a book on cranks. I believe one chapter is on FLT. === Subject: Re: False proofs of FLT > Unfortunately Im from spain I cant have access to such books. I was > looking for a web site. Ah-so! :-) There are only simple false proofs on web sites. Choose any of them. There are no simple right proofs. You are welcome Tapio > Hi! > > Could you point me to a good source of interesting and short false > proofs of > FLT to check my personal-probably-wrong-too-short-and-simple-proof of > FLT? > > Underwood Dudley has a book on cranks. I believe one chapter is on FLT. === Subject: Re: False proofs of FLT > Hi! > Could you point me to a good source of interesting and short false proofs of > FLT to check my personal-probably-wrong-too-short-and-simple-proof of FLT? > TIA. > N. named James Harris. David === Subject: Re: False proofs of FLT > Hi! > Could you point me to a good source of interesting and short false proofs > of > FLT to check my personal-probably-wrong-too-short-and-simple-proof of FLT? > TIA. > N. > named James Harris. > David Ive heard about him, but I was looking for Œsimplerı proofs. i.e. Proofs using elementary math. === Subject: Re: False proofs of FLT One false proof can be this one. If you take a geometric aproach and start to make a Proof of Pithagoream Theorem, then you do the same for grade 3 and then generalize to higher degrees you obtain the wrong proof (this false proof can represent an insight of what is a 3D representation that Fermat developed although Descartes is considered father of 2D Analitical Geometry) The Œproofı ----------- Consider three squares A,B and C with sides a>b>c. Then you draw the smaller ones into the greater in the same diagonal but in opposite corners so you have a new square which is the intersection of B and C and also you obtain two rectangles belonging to A that dont intersect with nothing. The resulting equation is (b+c-a)^2=2(a-b)(a-c) The same you can do but for cubes and you obtain an intersecting cube (from cube B and C) and some prisms that belongs to cube A and dont intersect with B or C. You do the same that before and obtain this (b+c-a)^3=3(a-b)(a-c)(b+c) and to make the post shorter, the proof is explained here http://mathpages.com/home/kmath367.htm So the wrong proof can be obtained due to an ilumination if you visualize tessellations of cubes for degrees higher than 3 (x^4=x*x^3 and you have a prism formed by x cubes and so on) Also you can say something about Fermatıs Little Theorem taking this geometric approach and you obtain equations like y(y^(n-1)-1)=Prime*F(y) and it is obvious that if y is not divided by a Prime then you have the famous Fermatıs Little Theorem. My conclusion is that Fermat didnt have formal proofs, only geometric ones like his beloved greeks, so he challenged some mathematicians to obtain the real formal proofs. === Subject: roots of unity in Koblitz Hi people, Iım currently trying to understand some stuff from Algebraic Aspects of Cryptography and stumbled over the following : (We have a Field F[p^f] where p is prime) 12. Let d = gcd(k,(p^f)-1). Since d | (p^f)-1, the cyclic group F*[p^f] clearly has d d-th roots of unity. Each of them is also a k-th root. Problem is, that this is absolutely not clear to me ;) I have tried an example : p = 2 f = 4 k = 5 so gcd(5,15) = 5, so I should be able to Ŝnd 5 5th roots of unity, but I can only Ŝnd one (Its 1). Probably Iım missing something here, can anyone else Ŝnd other 5th roots of unity here ? greets Dennis === Subject: Re: roots of unity in Koblitz >Hi people, >Iım currently trying to understand some stuff from Algebraic Aspects of >Cryptography and stumbled over the following : >(We have a Field F[p^f] where p is prime) >12. Let d = gcd(k,(p^f)-1). Since d | (p^f)-1, the cyclic group F*[p^f] >clearly has d d-th roots of unity. Each of them is also a k-th root. >Problem is, that this is absolutely not clear to me ;) >I have tried an example : >p = 2 >f = 4 >k = 5 >so gcd(5,15) = 5, so I should be able to Ŝnd 5 5th roots of unity, but I >can only Ŝnd one (Its 1). >Probably Iım missing something here, can anyone else Ŝnd other 5th roots of >unity here ? The polynomial x^5 - 1 factors as (x - 1)(x^4 + x^3 + x^2 + x + 1) over GF(2). The roots of the irreducible quartic belong to GF(2^4). -- John Adams served two terms as Vice President and one as President, but lost reelection. Later his son became President despite losing the popular vote. That son lost his reelection attempt badly. Now history is repeating itself. pmontgom@cwi.nl Microsoft Research and CWI Home: San Rafael, California === Subject: Re: roots of unity in Koblitz > Iım currently trying to understand some stuff from Algebraic Aspects of > Cryptography and stumbled over the following : > (We have a Field F[p^f] where p is prime) > 12. Let d = gcd(k,(p^f)-1). Since d | (p^f)-1, the cyclic group F*[p^f] > clearly has d d-th roots of unity. Each of them is also a k-th root. > Problem is, that this is absolutely not clear to me ;) > I have tried an example : > p = 2 > f = 4 > k = 5 > so gcd(5,15) = 5, so I should be able to Ŝnd 5 5th roots of unity, but I > can only Ŝnd one (Its 1). > Probably Iım missing something here, can anyone else Ŝnd other 5th roots of > unity here ? Sure: exp(2pi i/5), exp(4pi i/5), exp(6pi i/5), and exp(8pi i/5). Jose Carlos Santos === Subject: Re: roots of unity in Koblitz >> Iım currently trying to understand some stuff from Algebraic Aspects of >> Cryptography and stumbled over the following : >> (We have a Field F[p^f] where p is prime) >> 12. Let d = gcd(k,(p^f)-1). Since d | (p^f)-1, the cyclic group F*[p^f] >> clearly has d d-th roots of unity. Each of them is also a k-th root. >> Problem is, that this is absolutely not clear to me ;) >> I have tried an example : >> p = 2 >> f = 4 >> k = 5 >> so gcd(5,15) = 5, so I should be able to Ŝnd 5 5th roots of unity, but I >> can only Ŝnd one (Its 1). >> Probably Iım missing something here, can anyone else Ŝnd other 5th roots >> of unity here ? > Sure: exp(2pi i/5), exp(4pi i/5), exp(6pi i/5), and exp(8pi i/5). Hmmm. Not really characteristic 2 entities ... :-( To answer the OPıs question one needs to know how he is representing elements of F_16. Of course the cube of each nonzero element of F_16 is a 5-th root of unity. -- Robin Chapman, www.maths.ex.ac.uk/~rjc/rjc.html Lacan, Jacques, 79, 91-92; mistakes his penis for a square root, 88-9 Francis Wheen, _How Mumbo-Jumbo Conquered the World_ === Subject: Re: roots of unity in Koblitz > so gcd(5,15) = 5, so I should be able to Ŝnd 5 5th roots of unity, but I > can only Ŝnd one (Its 1). > Probably Iım missing something here, can anyone else Ŝnd other 5th roots > of unity here ? >> Sure: exp(2pi i/5), exp(4pi i/5), exp(6pi i/5), and exp(8pi i/5). > Hmmm. Not really characteristic 2 entities ... :-( I *really* have to read the questions more carefully before trying to answer them. :-( Jose Carlos Santos === Subject: re:a new way round diagonalisation-one inŜnity?meta set theory One more example with meta set theory: We deŜne the power set P(m) as: x e(t+1) P(m) :<-> ( y e(t) x -> y e(t) m ) ( 0 e(t+1) P(m), m e(t+1) P(m) ) The famous result of Cantor was, that there exists no bijection beween m and P(m). In meta set theory this is not so: If we have for m the set A of all sets, P(m) = P(A) is deŜned as x e(t+1) P(A) :<-> ( y e(t) x -> y e(t) A) , this is true for all sets x, therefore P(A) = A, with identity as bijection. Or with Cantors proof: m be a set, f a bijection m <-> P(m). x e(t+1) h(f) :<-> x e(t) m : x -e(t) f(x) (In classical set theory h(f) -= f(x) for all x e m, as if h(f) = f(x) then : if x e f(x) then x -e h(f)=F(x), therefore x -e f(x) therefore x e h(f) and x -e h(f)=f(x).# In meta set theory if h(f) =(t+1) f(x) (or if h(f) =(...) f(x)): if x e(t+1) h(f) then x -e(t) f(x) =(...) h(f). This is no contradiction, as x may be element an non-element of h(f) in different levels. There is no need for different kinds of inŜnity for sets in meta set theory. Oskar Trestone ---------------------------------------------------------- ** SPEED ** RETENTION ** COMPLETION ** ANONYMITY ** ---------------------------------------------------------- http://www.usenet.com http://www.newsfeed.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= 19 East/West-Coast Specialized Servers - Total Privacy via Encryption =--- === Subject: re:Simple Grid-Game #1 oops... from the looks of it it appears as though I proved the obvious in a roundabout manner. Actually, in an incorrect manner, I showed that a contradiction implies a true statement. Actually, I left out the actual question. Is a game which permits a draw called a futile game because it is gauranteed to end in a draw if played properly? If the neither categorical nor futile above is changed to not categorical, hence futile (permitting a draw) does the above constitute a correct proof that the end result is a draw? Does a similar induction work to show that a categorical game is unfair. 1. player one is the last to play and wins. 2. player two could not have prevented this win on his last move, otherwise, he did not play properly. 3. So player one actually played a win on his move before the last. 4. player two could not have prevented... etc. to the Ŝrst move of the game (which may have been made by either player). What if you do not assume as I did that there are only two players? ---------------------------------------------------------- ** SPEED ** RETENTION ** COMPLETION ** ANONYMITY ** ---------------------------------------------------------- http://www.usenet.com http://www.newsfeed.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= 19 East/West-Coast Specialized Servers - Total Privacy via Encryption =--- === Subject: re:Simple Grid-Game #1 I saw a thing in math world that says that there is a strategy for one of the two to win since there is no possibility of a draw. http://mathworld.wolfram.com/CategoricalGame.html I also saw something else, the deŜnition of a futile game is one which permits a draw (tie) when played properly by both players. Now given a game, neither futile or Categorical, if player one plays properly, he is not gauranteed to win. Then player two plays case 1: he plays and is guaranteed to win. this is a contradiction. case 2: he plays and player one is gauranteed to win. Then he didnıt play properly. contradiction. case 3: since the game is not categorical there is a case 3. He plays and neither player is now guaranteed to win. back to player one. case 1: he plays and is guaranteed to win. this is a contradiction (case 2 above). case 2: he plays and player two is gauranteed to win. Then he didnıt play properly. contradiction. case 3: He plays and neither player is now guaranteed to win. etc. therefore, the winning move is never possible. Is there a ŝaw in this reasoning, granted that I donıt really know what a proper play is, but it seems as though it should be a play that doesnıt guarantee the other a win. If this is right, then any game is either futile or categorical and unfair. Even chess. ---------------------------------------------------------- ** SPEED ** RETENTION ** COMPLETION ** ANONYMITY ** ---------------------------------------------------------- http://www.usenet.com http://www.newsfeed.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= 19 East/West-Coast Specialized Servers - Total Privacy via Encryption =--- === Subject: normed space In a proof, they use a fact that I canıt understand. It says: suppose X is a normed vector space and M is a proper closed subspace of X. We can deŜne norm on X/M as ||x+M||=inf {||x+y||: y in M}. The book mentions that for any e>0, there is x in X such that ||x||=1 & ||x+M||>= 1-e. Can anyone see why? === Subject: Re: normed space > In a proof, they use a fact that I canıt understand. It says: > suppose X is a normed vector space and M is a proper closed subspace of > X. > We can deŜne norm on X/M as ||x+M||=inf {||x+y||: y in M}. > The book mentions that for any e>0, there is x in X such that ||x||=1 & > ||x+M||>= 1-e. > Can anyone see why? Choose a coset with nonzero norm. Say the coset of z has norm a>0. Then by deŜnition of the norm, we may choose y in M so that ||z+y|| is as close as we like to a. Your vector will be x=(z+y)/||z+y|| where y is such that ||z+y|| I remember a short biography written by P. Cartier on the occasion of the speculative remarks on Grothendieckıs current mental state. -- Allan Adler * Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and * comments do not reŝect in any way on MIT. Also, I am nowhere near Boston. === Subject: Re: Alexander Grothedieck biography? >Has anyone written, or is currently writing, a biography of Alexander >timelines. Perhaps there are some biographies written in other languages >that my searches arenıt turning up. > (in french) that unfortunately is not in print. Only (copies) of > notes of it are circulating ... It is being translated (in short takes) by Roy Lisker who needs Ŝnancial help to continue it. Google him or fermentpress to get more details. === Subject: Four-Color Theorem Am I right in saying that there are no short proofs of the four-color theorem to date? In 1976 Appel and Haken proved it using computers, and in 1996 Robertson, Seymour and Thomas improved and shortened the proof. Has there been any news since that time? And what of Hadwigerıs conjecture? I ask because I want to prove them, hehe. -Greg === Subject: Re: contravariant tensor Ŝelds, differential operators and quantisation In the meantime, I worked out the transformation rule for the components of a second order differential operator in coordinates. By this, I mean something of the form a^ij d^2/(dx^i dx^j) where the a^ij are the component functions and d is the curly d partial differential operator. The transformation will get pretty complicated for higher orders, and it does not seem to have to do anything with tensors - what kind of structure is it then? -- hang my head drown my fear till you all just disappear reverse my forename for mail! - saibot === Subject: Re: 111,111,111 x 111,111,111 = 12,345,678,987,654,321 > Until you mentioned 666 I had no idea what signiŜcance it had to some > people. Actually, the signiŜcance exists only in the mind of the beholder. If I showed you a three-leaf clover I found in my yard, you would probably say So what? Thereıs a lot of them about. The whole trick is to take something thatıs fundamentally easy and give it an esoteric appearance. For example, take the factors of 111,111,111: 3 * 3 * 37 * 333667 Looks like we just missed the boat here. We got 37 instead of 36 and the last three digits of the last factor are 667, not 666. But a good numerologist doesnıt let wrong numbers get in the way. 37 is 36 + 1 and the 36th triangular number (666) added to the 1st triangular number (1) is 667, matching the last three digits of the last factor. And note that the Ŝrst three digits of the last factor (333) are exactly half of 666. Not only that, but 3 * 3 * 37 equals 333! There are so many math operations (addition, subtraction, mutiplcation, etc.) and character string operations (concatenation, splitting, reversing, etc.) available that you can relate any two numbers as easily as you can Ŝnd a three-leaf clover. All you need is some lame rationalization (I reversed the digits because the Beast is the Anti-Christ) for why you used what you did and glossed over the parts that didnıt Ŝt. And the best ally of a lame rationalization is repetition. Look, 37 is 36+1. And 667 is 666+1! Spooky! > I am not a mathematician but these things are interesting to play with and > learn about.. Yep. Itıs a lot of fun. But is just that: fun. > Dave === >Subject: Re: 111,111,111 x 111,111,111 = 12,345,678,987,654,321 > > >> A Ŝend showed me this: >> >> 111,111,111 x 111,111,111 = 12,345,678,987,654,321 > >Iıd have thought a Ŝend would be more interested in 666. > > Yes, but the Ŝend is subtle. The LHS has 18 ones, and 18 is 6+6+6. > And on the RHS, the digits sum to 81, which is 18 backwards. > So if you ŝip the 81 around and add it to the other 18, you get > 36, the sum of integers of which is 666! > > Spooky, eh? > > > Hereıs one I learned recently: > Sum(n = 1 --> 7) [(P_n)^2] = 666 > ( P_n = nth prime ) === Subject: [tensor algebra] tensorŜeld problem Hereıs the problem: DeŜnitions: M is a real manifold. T(M) is the space of smooth vectorŜelds on M. T^1(M) is the space of 1-forms on M. ------------------------------------------------- An important property of tensor Ŝelds is that they are multilinear over the space of smooth functions. Given {X_i} smooth vectorŜelds, and {w^j} 1-forms. Given a (k,l)-tensorŜeld F. Then the function F(X_1, ..., X_k, w^1, ..., w^l) is smooth, and thus F induces a map: F : T^1(M) x .... x T^1(M) x T(M) x .... x T(M) ---> C^infty(M) The map F is multilinear over C^infty(M), meaning for functions f, g, in C^infty(M) and any smooth vectorŜelds or covectorŜelds alpha and beta, F(..., f * alpha + g * beta, ...) = f F(..., alpha , ...) + g F(..., beta, ...). ------------------------- The converse is also true. Any such multilinear map deŜnes a tensorŜeld. A map t: T^1(M) x .... x T^1(M) x T(M) x .... x T(M) ---> C^infty(M) is induced by a (k,l) tensorŜeld as above if and only if it is multilinear over C^infty(M). And a map t: T^1(M) x .... x T^1(M) x T(M) x .... x T(M) ---> T(M) is induced by a (k,l+1) tensorŜeld if and only if it is multilinear over C^infty(M). ------------------- How do i have to prove the converse? === Subject: Old Mac-based graphing calculator from Harvard, circa 1998? Does anyone have a copy of a graphing calculator application from Harvard University, circa 1989? It was standard issue for Math 21a, Multivariable Calculus. It was amazing; if you gave it a multivariable function it would plot vector Ŝelds, compute line integrals, curl, ŝux, etc. I didnıt have a Mac at the time, so I had to schlepp my ŝoppy downstairs to my dorm-mates room and kick him off his Tetris game so I could use his Mac. After graduating I promptly misplaced the ŝoppy. No doubt Mathematica would do this also, but this app was free (with tuition :), and it Ŝt on a ŝoppy. Has anyone else even seen this? I donıt even remember the name of it. === Subject: Re: Old Mac-based graphing calculator from Harvard, circa 1998? > Does anyone have a copy of a graphing calculator application from > Harvard University, circa 1989? It was standard issue for Math 21a, > Multivariable Calculus. > It was amazing; if you gave it a multivariable function it would plot > vector Ŝelds, compute line integrals, curl, ŝux, etc. > I didnıt have a Mac at the time, so I had to schlepp my ŝoppy > downstairs to my dorm-mates room and kick him off his Tetris game so I > could use his Mac. After graduating I promptly misplaced the ŝoppy. > No doubt Mathematica would do this also, but this app was free (with > tuition :), and it Ŝt on a ŝoppy. > Has anyone else even seen this? I donıt even remember the name of it. It may be the one named simply Graphing Calculator, which has since gone commercial, in which case see http://www.paciŜct.com/ === Subject: Re: Old Mac-based graphing calculator from Harvard, circa 1998? >> Does anyone have a copy of a graphing calculator application from >> Harvard University, circa 1989? It was standard issue for Math 21a, >> Multivariable Calculus. >> It was amazing; if you gave it a multivariable function it would plot >> vector Ŝelds, compute line integrals, curl, ŝux, etc. >> I didnıt have a Mac at the time, so I had to schlepp my ŝoppy >> downstairs to my dorm-mates room and kick him off his Tetris game so I >> could use his Mac. After graduating I promptly misplaced the ŝoppy. >> No doubt Mathematica would do this also, but this app was free (with >> tuition :), and it Ŝt on a ŝoppy. >> Has anyone else even seen this? I donıt even remember the name of it. > It may be the one named simply Graphing Calculator, > which has since gone commercial, > in which case see > http://www.paciŜct.com/ It canıt be the same. Appleıs Graphing Calculator was a PowerPC-only app, and all Macs in 1989 were 68K. -- Dave Seaman Judge Yohnıs mistakes revealed in Mumia Abu-Jamal ruling. === Subject: Bourbaki Volumes (was Re: Cosets) Originator: jgamble@ripco.com (John M. Gamble) >> lol. I have a better suggestion : Bourbaki. Any advance ? >> Pascal >Unfortunately, Bourbakiıs ones are already lost forever ... I tried to get >the Ŝrst topology volumes (in French of course) but I couldnt -my only >chance would be to scan every single page of the volumes Iıd borrow from my >uni. library-. Could you expand on this a little? Why are they lost forever? Published during the self-destructing-paper era? Limited print run? Other? -- -john February 28 1997: Last day libraries could order catalogue cards from the Library of Congress. === Subject: Re: Bourbaki Volumes (was Re: Cosets) > Could you expand on this a little? Why are they lost forever? > Published during the self-destructing-paper era? > Limited print run? > Other? For instance the Ŝrst volumes of Topology (I think Vol. I, II and III or so) are not printed anymore (in French, I mean; getting them in English would be ok too, but iıd lose much of their semantic value). The best I could do was to borrow them from my universityıs library: I got two old books from the 60ıs, hardly bound with the pages almost vanishing into ashes when you touch them (the woman was looking at me as if I was some sorcerer or I dunno which freak, all the more than I had to bother her for almost half an hour because the books were in a remote dark room buried in a secret place of the uni. lol); I didnıt have the courage to scan each of the thounsands of pages, and I had to give them back -you can borrow books only for one month, even though, hey, those books hadnıt been borrowed for some 9 years-. Theyıre now lost forever. === Subject: Re: Bourbaki Volumes (was Re: Cosets) >>Could you expand on this a little? Why are they lost forever? >>Published during the self-destructing-paper era? >>Limited print run? >>Other? > For instance the Ŝrst volumes of Topology (I think Vol. I, II and III or > so) are not printed anymore (in French, I mean; getting them in English > would be ok too, but iıd lose much of their semantic value). > The best I could do was to borrow them from my universityıs library: I got > two old books from the 60ıs, hardly bound with the pages almost vanishing > into ashes when you touch them (the woman was looking at me as if I was some > sorcerer or I dunno which freak, all the more than I had to bother her for > almost half an hour because the books were in a remote dark room buried in a > secret place of the uni. lol); I didnıt have the courage to scan each of the > thounsands of pages, and I had to give them back -you can borrow books only > for one month, even though, hey, those books hadnıt been borrowed for some 9 > years-. Theyıre now lost forever. Bourbakiıs General Topology in English is available from amazon.com. They also have a used copy of Chap. 5 - 10 in French for sale. Many used copies of Bourbaki books are available from Abebooks, real cheap http://www.abebooks.com === Subject: Re: Bourbaki Volumes (was Re: Cosets) > Could you expand on this a little? Why are they lost forever? > Published during the self-destructing-paper era? > Limited print run? > Other? > For instance the Ŝrst volumes of Topology (I think Vol. I, II and III or > so) are not printed anymore (in French, I mean; getting them in English > would be ok too, but iıd lose much of their semantic value). > The best I could do was to borrow them from my universityıs library: I got > two old books from the 60ıs, hardly bound with the pages almost vanishing > into ashes when you touch them (the woman was looking at me as if I was some > sorcerer or I dunno which freak, all the more than I had to bother her for > almost half an hour because the books were in a remote dark room buried in a > secret place of the uni. lol); I didnıt have the courage to scan each of the > thounsands of pages, and I had to give them back -you can borrow books only > for one month, even though, hey, those books hadnıt been borrowed for some 9 > years-. Theyıre now lost forever. You might try alt.binaries.e-book. It is surprising what turns up there - you might get lucky. Try REQ:Bourbaki as your subject. -- Paul Sperry Columbia, SC (USA) === Subject: test test === Subject: Question for Harris have found many different posts of yours with valid counter-arguments by other posters. Since you are still making such contentions, can you please deŜne a short and unassailable mathematical proof supporting your claims? === Subject: Re: Question for Harris > have found many different posts of yours with valid counter-arguments > by other posters. > Since you are still making such contentions, can you please deŜne a > short and unassailable mathematical proof supporting your claims? Why do you care, crackpot? Are you trying to get some pointers in being a kook from Harris? === Subject: Re: Question for Harris > have found many different posts of yours with valid counter-arguments > by other posters. > Since you are still making such contentions, can you please deŜne a > short and unassailable mathematical proof supporting your claims? JSH _never_ responds to questions. Gib === Subject: Re: Great-circle radius of ellipsoid > pi r^2 = pi a b >> or >> = Pi * [a^3 * b]^.5 > Wrong. The above lacks a logical derivation. >> ** OR ** >> = Pi * .5 * [a^2 + .5*(a^2 + b^2)] >> = Pi * .25 * [3a^2 + b^2] > r = sqrt(ab). >> or >> = [a^3 * b]^.25 >> ** OR ** >> = [.5 * (a^2 + .5*)]^.5 = [.25 * (3a^2 + b^2)]^.5 >> Look at it this way: >> Semi-axes . Arcradii >> | /| >> | a^2/b | >> | | >> | | >> | = b | = Rr = a * E2ı{0> | / | / ~=~ [a*b]^.5 >> | | ~=~ [.5*(a^2+b^2)]^.5 >> | b^2/a | >> |_______________ `.________________ >> = a = a >> Mean Mean >> Radius ~=~ [a*b]^.5 Arcradius ~=~ [a*Rr]^.5 >> ~=~ [.5*(a^2+b^2)]^.5 ~=~ [a*(a*b)^.5]^.5 >> = [a^3*b]^.25 ~=~ .5*[a+Rr] >> ~=~ [.5*(a+.5*)]^.5 >> = [.25*(3a^2+b^2)]^.5 >> Thus, *EVEN* if you believe the mean arcradius is the geometric >> mean, the actual gm should be [a^3*b]^.25, not [a*b]^.5! P=) > The solution you have given is arbitrary and does not follow a > consistent derivation, and with that sort of reasoning, there would > be inŜnite solutions. > The answer is simply: > Area of circle = Area of ellipse ^^^^^^^ > r = sqrt(ab). Right, for an *ELLIPSE* (the left, semi-axes diagram)! What is being discussed here is a 3-D ellipsoid (the right, arcradii diagram). > If this is wrong as you contend, explain why. I think the problem is everyone is viewing the ellipsoid as being composed of equi-sized meridional ellipses and/or meridionally parallel semi-ellipses. While that may be *A* valid interpretation, it is not *THE* proper interpretation for this discussion--the Ŝnding of the great circle arcradius of best Ŝt for the spheroid/ellipsoid. As such, the relevant approach to analyzing the form of an ellipsoid is to view it as being made up of unique great ellipses (GEs), where a meridian is the maximally elliptic GE and the equuator is the minimally elliptic GE, a great circle. So, for a *3-D ELLIPSOID*, one is averaging the arcradii of all of the different GEs, hence the simplest 2-point average would be between a meridian (~=~ [a*b]^.5 or .5*[a+b] or [.5*(a^2+b^2)]^.5, to name the most common)--the maximum GE--and the equator, which, being a great circle and having an equal radius throughout, always equals a. GEs, as all geodetic lines travel along them, can also be viewed as ARC PATHs (APs). Let a = 6378.135 and b = 6356.75. The mean meridional arcradius (Rr) = 6367.4469888342: [a*b]^.5 = 6367.43352233; 2/[1/a + 1/b] = 6367.42454467; .5 * [a + b] = 6367.4425; [.5 * (a^2 + b^2)]^.5 = 6367.45147766; [.5 * (a^1.5 + b^1.5)]^(1/1.5) = 6367.4469888334; The mid-GE possibilities work out to the following: Lat1 = 0, Long2 - Long1 = 90, Lat2 = 45, AP = 45.09601377, mean arcradius = 6372.80780848; Lat2 = 45.09601444, AP = 45, mean arcradius = 6372.78989792; (.5 * [6372.80780848 + 6372.78989792] = 6372.79885320) Lat2 = AP = 45.04800712, mean arcradius = 6372.79885325 (the isopathic mid-GE (the concept and process discussed in a separate ) Keeping in mind that--given the minimal ellipticity involved--the trapezoidal 3-point average provides an integration to about .0000001, the global great circle arcradius of best Ŝt using the three different differentiating methods produce: .25 * (Rr + 2*6372.80780848 + a) = 6372.7994014; .25 * (Rr + 2*6372.78989792 + a) = 6372.7904462; .25 * (Rr + 2*6372.79885325 + a) = 6372.7949238; = .5 * [6372.7994014 + 6372.7904462] Now compare the aforementioned approximations: [a * Rr]^.5 = 6372.78875377; [a^3 * b]^.5 = 6372.78201486; .5 * [a + Rr] = 6372.79099442; [.25 * (3a^2 + b^2)]^.5 = 6372.79547760; Wouldnıt you agree that [.25 * (3a^2 + b^2)]^.5 is by far the best approximation--if not another ACTUAL global mean, via some other differentiation? Letting a = 10000, down to a b value of about 8385, the maximum difference from the isopathic is -.74186, whereupon the deviation reverses until they equate at a b value of about 7624.5 and [.25 * (3a^2 + b^2)]^.5 remains greater than the isopathic for lesser b values (at 7071.067 the difference is +1.94, and at 6000, +11.03)--thus even if the isopathic IS the only true great circle arcradius of best Ŝt, for general purposes [.25 * (3a^2 + b^2)]^.5 appears adequate. As I noted in my original reply, given the relationship of .5 * [a^2 + b^2] to the integrand^2 of the elliptic integral of the second kind, there is still a good possibility that [.25 * (3a^2 + b^2)]^.5 may be a closed-form reduction to another legitimate great ellipse differentiation. Or, rather than arcradius, perhaps [.25 * (3a^2 + b^2)]^.5 is the global average of the *semi-axes* along each GE--i.e., change b to Radius{Lat} for each GE and calculate Rr for each GE (thus Radius{0} equals a--with Rr equaling a--and Radius{90} equals b--with Rr equaling the meridional Rr)--but I havenıt really explored that approach, so it is just a random theory at this point. ~Kaimbridge~ ----- WantedKaimbridge (w/mugshot!): http://www.angelŜre.com/ma2/digitology/Wanted_KMGC.html ---------- DigitologyThe Grand Theory Of The Universe: http://www.angelŜre.com/ma2/digitology/index.html ***** Void Where Permitted; Limit 0 Per Customer. ***** === Subject: Re: Integer Occurs Same # Of Times In These Sequences [My other reply to this thread is not a duplicate of this reply.] We can use the result below to get an integral identity. (Most likely there is an easier way to prove this.) Let f1(x) and f2(x) be real->real continuous monotonically increasing functions, where f1(0) = f2(0) = 0. Let g1(x) and g2(x) be such that g1(f1(x)) = x and g2(f2(x)) = x for all x. Let a(x) be any real -> real integrable function (where integral below exists and converges), where the derivative of a(x) exists. Let A(x) be the derivative of a(x) at x. Then: integral{0 to oo} (a(f1(x)+x) + a(f2(x)+x) - a(x) - a(f1(x)+f2(x)+x)) dx = integral{0 to oo} integral{0 to oo} A(max(g1(x),g2(y))+x+y) dy dx (Maybe.) Using the result in my other reply to this thread, we can get the simpler integral identity: integral{0 to oo} a(f(x)+g(x)+x) dx = integral{0 to oo} integral{0 to oo} -A(max(f(x),g(y))+x+y) dy dx (Maybe.) Leroy Quet > I wonder if anyone has a clever proof of the result below. > -- > Let f1()and f2() be (almost) any real-real continuous monotonically > increasing functions. > Let g1() and g2() be the inverses of f1() and f2(), > f1(g1(x)) = x and f2(g2(x)) = x for all x. > And let each f and g be such that > f1(1), f2(1), g1(1), and g2(1) all exist and are each >= 0. > (I am a little unsure if these conditions are necessary or > sufŜcient.) > Let m be any positive integer. > Then: > (the number of times m occurs in the sequence > {ŝoor(f1(k)) + k}) > (the number of times m occurs in the sequence > {ŝoor(f2(k)) + k}) > (the number of times m occurs in the sequence > {ceiling(max(g1(k),g2(j))) + k + j - 2}), > is equal to > (the number of times m occurs in the sequence > {k}) > (the number of times m occurs in the sequence > {ŝoor(f1(k)) + ŝoor(f2(k)) + k}) > (the number of times m occurs in the sequence > {ceiling(max(g1(k),g2(j))) + k + j - 1}), > for j and k = positive integers (independent between different > sequences). > (max(x,y) means maximum of x or y.) > Example: > For m = 12, > f1(k) = k^2, > f2(k) = 2^k, > g1(k) = sqrt(k), > g2(k) =ln(k)/ln(2), > we have: > ŝoor(f1(k)) + k: k = 3 > ŝoor(f2(k)) + k: no kıs > ceiling(max(g1(k),g2(j))) + k + j - 2: > k = 9, j = 2; > k = 8, j = 3; > k = 7, j = 4; > k = 6, j = 5; > k = 5, j = 6; > k = 4, j = 7; > k = 3, j = 8; > k = 1, j = 9 > So we have 9 representations of 12 total among the Ŝrst 3 sequences. > Counting representations among the last 3 sequences, we have: > k: k = 12 (obviously) > ŝoor(f1(k)) + ŝoor(f2(k)) + k: no kıs > ceiling(max(g1(k),g2(j))) + k + j - 1: > k = 9, j = 1; > k = 8, j = 2; > k = 7, j = 3; > k = 6, j = 4; > k = 5, j = 5; > k = 4, j = 6; > k = 3, j = 7; > k = 2, j = 8 > So, again, we have 9 representations. > (Amazing) > As a (possibly fun) exercise, try to prove yourself this result is > true for all positive integers m and for all fıs and gıs (with the > mentioned restrictions). > Leroy Quet === Subject: Re: Integer Occurs Same # Of Times In These Sequences [My other reply to this thread {which I still have to post as of me writing this} is not a duplicate of this reply.] Letting f(x) = f1(x), and having the inverse of f(x), g(x), replace f2(x), we can use, in conjunction with the result in this threadıs original post, the related but simpler result at to get the following: If f(x) is any real -> real continuous monotonically increasing function, where f(1) and g(1) are deŜned and are both >= 0, g(f(x)) =x for all x, then: any particular positive integer m occurs the same number of times in {k + j + max(ŝoor(f(k))+1,ceiling(g(j))) - 2} as in both {k + j + max(ŝoor(f(k))+1,ceiling(g(j))) - 1} and {ŝoor(f(k)) + ceiling(g(k)) + k - 1} together. And if f(k) and g(k) never equal an integer for all positive integers k, the result above can be simpliŜed slightly to: the positive integer m occurs the same number of times in {k + j + ŝoor(max(f(k),g(j))) - 1} as in both {k + j + ŝoor(max(f(k),g(j)))} and {ŝoor(f(k)) + ŝoor(g(k)) + k} together. Leroy Quet > I wonder if anyone has a clever proof of the result below. > -- > Let f1()and f2() be (almost) any real-real continuous monotonically > increasing functions. > Let g1() and g2() be the inverses of f1() and f2(), > f1(g1(x)) = x and f2(g2(x)) = x for all x. > And let each f and g be such that > f1(1), f2(1), g1(1), and g2(1) all exist and are each >= 0. > (I am a little unsure if these conditions are necessary or > sufŜcient.) > Let m be any positive integer. > Then: > (the number of times m occurs in the sequence > {ŝoor(f1(k)) + k}) > (the number of times m occurs in the sequence > {ŝoor(f2(k)) + k}) > (the number of times m occurs in the sequence > {ceiling(max(g1(k),g2(j))) + k + j - 2}), > is equal to > (the number of times m occurs in the sequence > {k}) > (the number of times m occurs in the sequence > {ŝoor(f1(k)) + ŝoor(f2(k)) + k}) > (the number of times m occurs in the sequence > {ceiling(max(g1(k),g2(j))) + k + j - 1}), > for j and k = positive integers (independent between different > sequences). > (max(x,y) means maximum of x or y.) > Example: > For m = 12, > f1(k) = k^2, > f2(k) = 2^k, > g1(k) = sqrt(k), > g2(k) =ln(k)/ln(2), > we have: > ŝoor(f1(k)) + k: k = 3 > ŝoor(f2(k)) + k: no kıs > ceiling(max(g1(k),g2(j))) + k + j - 2: > k = 9, j = 2; > k = 8, j = 3; > k = 7, j = 4; > k = 6, j = 5; > k = 5, j = 6; > k = 4, j = 7; > k = 3, j = 8; > k = 1, j = 9 > So we have 9 representations of 12 total among the Ŝrst 3 sequences. > Counting representations among the last 3 sequences, we have: > k: k = 12 (obviously) > ŝoor(f1(k)) + ŝoor(f2(k)) + k: no kıs > ceiling(max(g1(k),g2(j))) + k + j - 1: > k = 9, j = 1; > k = 8, j = 2; > k = 7, j = 3; > k = 6, j = 4; > k = 5, j = 5; > k = 4, j = 6; > k = 3, j = 7; > k = 2, j = 8 > So, again, we have 9 representations. > (Amazing) > As a (possibly fun) exercise, try to prove yourself this result is > true for all positive integers m and for all fıs and gıs (with the > mentioned restrictions). > Leroy Quet === Subject: velocities in opposite directions by support1.mathforum.org (8.11.6/8.11.6/The Math Forum, $Revision: 1.9 primary) id i4PIm7b17257; Question: If one car has a radar gun and is heading south at appx. 10 mph and another car is heading north (exact opposite direction) at 40 mph, will that radar gun read 50 mph. why or why not? Deanna === Subject: Re: velocities in opposite directions > Question: > If one car has a radar gun and is heading south at appx. 10 mph and another > car is heading north (exact opposite direction) at 40 mph, will that radar > gun read 50 mph. why or why not? > Deanna At relative vealocities so much less that the speed of light, the radar gun should read close enough to 50 mph for all practical purposes. === Subject: Re: velocities in opposite directions : > Question: : > : > If one car has a radar gun and is heading south at appx. 10 mph and another : > car is heading north (exact opposite direction) at 40 mph, will that radar : > gun read 50 mph. why or why not? : > : > Deanna : > : At relative vealocities so much less that the speed of light, the radar : gun should read close enough to 50 mph for all practical purposes. Velocity is a vector (whose maginitude is speed), vectors add/subtract, so the net velocity = 50 mph heading north. The velocities involved are far less than c = speed of radar beam, so their magnitudes dominate. === Subject: Re: resolving Willıs misunderstanding >>>>Letıs try a different approach, starting with deŜnitions of everything >>>>under consideration: >>>> >>>>We are talking about functions, but the real concern is what algorithms >>>>are used to compute those functions. For simplicityıs sake, we can >>>>restrict our discussion to functions mapping from the whole numbers to >>>>the whole numbers f:W->W. For an algorithm to correctly represent >>>>f(x)=y, it should start with input x and produce output y after Ŝnitely >>>>many steps, where each step is computed from the input and the previous >>>>steps. For a given function f, f may or may not be deŜned for all/any >>>>numbers in the whole numbers. As a result, the algorithm describing f >>>>is only required to be Ŝnite for those values of x for which f is >>>>deŜned. A function f with such an algorithm is in general called a >>>>partial function. A partial function f which is deŜned on all elements >>>>of the whole numbers is called a total function and is considered to be >>>>computable (or recursive). >>>> >>>>At this point, I believe we can start making some clear observations. >>>>First: the halting problem is only available for discussion if we a >>>>dealing with partial functions (which have algorithms that do not halt >>>>in Ŝnite time for some input values). >>>>Second: it appears to be your desire to discuss only total functions. >>>>Third: if we restrict ourselves to the total functions, discussing the >>>>halting problem is meaningless. >>>> >>>>A question that is relevent to the above: if we are restricting >>>>ourselves to total functions, is there a way to specify the algorithms >>>>of all total functions in such a way that there is no possibility of >>>>dealing with potentially partial functions? >>>> >>>>Before moving forward, do you have any comments on the above? Right now >>>>Iım just trying to set a framework for a detailed analysis, but if the >>>>basic framework is in dispute, I may need to adjust for that. >>> >>>The term to be deŜned is valid construction. Facts & FALSE -> anything. >>>> >>>>Agreed. I just wanted to make sure there were no objections before >>>>diving into the details. If the basic concepts to be deŜned in detail >>>>canıt be agreed on, then there isnıt much point in going further. >>>> >>>>For the moment, letıs allow functions to be n-ary for ease of notation. >>>>(It can be shown that we can restrict ourselves to unary functions, but >>>>they get messier.) >>>> >>>>Letıs start by deŜning primitive recursive functions These functions >>>>are guaranteed to be total functions and can be constructed by a Ŝnite >>>>number of applications of the following rules: >>>> >>>>1) f(x) = x+1 is primitive recursive >>>>2) f(x1,x2,...,xn) = m is primitive recursive where n and m >= 0 >>>>3) f(x1,x2,...,xn) = xi is primitive recursive where 0 < i <= n >>>>4) If g1, g2, .. gm, are primitive recursive and n-ary, and h is >>>>primitive recursive and m-ary then so is n-ary f deŜned as >>>> f(x1,x2,...,xn) = h(g1(x1,x2,...,xn),...,gm(x1,x2,...,xn)) >>>>5) For n>=1, if f is n-ary, g is (n-1)-ary, h is (n+1)-ary, and g and h >>>>are primitive recursive, then so is f deŜned by the following two rules: >>>>a) f(0,x2,x3,...,xn) = g(x2,x3,...,xn) >>>>b) f(x1+1,x2,x3,...,xn) = h(x1,f(x1,x2,...,xn),x2,...,xn) >>>> >>>>These rules appear (to my eye) to correspond with the deŜnition of a >>>>function guaranteed to halt you offered in another thread. >>>> >>>>Using these it is possible (though messy) to construct virtually all >>>>normal mathematical functions on the whole numbers. In particular, >>>>prime decomposition that will allow a number to represent a sequence of >>>>numbers by its prime decomposition. This enables us to formally get >>>>back to unary functions, if need be. >>>> >>>>Any comments at this point? The next question will be, do primitive >>>>recursive functions describe ALL total computable functions? >>> >>>nope >> >>Thereıs two questions, which one are you saying nope to? >>> >>>the 1st one, youıre supposed to be establishing the *next* question. >> >>Since there are only 5 rules for deriving primitive recursive functions, >> each one can be indexed based on what rules/functions are used to >>construct it. Consider one such indexing f0, f1, f2, f3, ... and let us >>construct a new function g0(x) = fx(x) + 1. Since fx can be formally >>considered unary, regarless of what n is for n-ary fx, and x determines >>the construction of f, g0(x) is deŜned on all x in the Whole Numbers. >>Moreover, we have included all partial recursive functions on our list >>f0, f1, f2, .... Therefore, g0(x) is a total function, it is >>computable, but it is not a primitive recursive function. By prepending >>g0(x) to the listing of primitive recursive functions, we can construct >>g1(x), g2(x), etc. Since there are multiple possible indexing schemes >>available for the primitive recursive functions, there are also multiple >>sequences of gi(x) available. >> >>Any issues with the above? >> >I got no idea what rule 5 does. It looks like a step -1 for loop that pushes the >parameters into the 2nd parameter of the 2nd parameter recursively, making >a longer parameter list every iteration. >>Itıs a construction similar to f(0) = c, f(x+1) = g(f(x)). The idea is >>to deŜne f(0) as something known, and deŜne f(x+1) in terms of f(x). >>The parameter list doesnıt actually get longer. >>construct a new function g0(x) = fx(x) + 1 >this is just diagonalisation all over again, f with godel x applied to its own godel number >with a modiŜcation. >>You are quite right. Now, does that invalidate the conclusion? >whatıs to stop me deŜning consistent p.r.f. where variable references are contextually free. >fx(x) = fx(y) for any x, y >>Those functions are described in construction 2, they are the constant >>functions. This has nothing to do with the validity or invalidity of >>the argument. >this stops dummy functions like the above that double usage the x in g0(x) >Iıve shown that getting a parameter x and using it for 2 arguments is >enough to change a total system to non halting system. >>We have not gotten to anything that does not halt. All that is being >>said is: a sufŜcient restriction to prevent functions that donıt halt >>also excludes some that do always halt. > ok, but how hard is it to exclude functions of type fx(x), theyıre the ones going > into inŜnite loops. what computation are they performing that canıt be > done some other way? The functions fx do not contain inŜnite loops. Nor do the functions gi built from them. The point was that the primitive recursive functions, while guaranteed to halt, are not *all* of the functions that are guaranteed to halt. The various functions gi are also guaranteed to halt, but they were found using a diagonal-style argument, and are therefore not primitive recursive. Having said all that, MOST functions and operations that we would want to perform would be primitive recursive functions, including things like the addition function, subtraction function (which produces 0 for negative results), multiplication, integer division, modular division, exponentiation, etc. As long as the computations can be broken down into the 5 rules applied to various primitive recursive functions, we are good to go. So far, there are no inŜnite loops, and everything is guaranteed to halt. Itıs just that not everything that halts is primitive recursive. The trick is to see if we can Ŝnd something that will include ALL functions that halt, and still exclude those that donıt. -- Will Twentyman email: wtwentyman at copper dot net === Subject: Re: resolving Willıs misunderstanding >>>>Letıs try a different approach, starting with deŜnitions of everything >>>>under consideration: >>>> >>>>We are talking about functions, but the real concern is what algorithms >>>>are used to compute those functions. For simplicityıs sake, we can >>>>restrict our discussion to functions mapping from the whole numbers to >>>>the whole numbers f:W->W. For an algorithm to correctly represent >>>>f(x)=y, it should start with input x and produce output y after Ŝnitely >>>>many steps, where each step is computed from the input and the previous >>>>steps. For a given function f, f may or may not be deŜned for all/any >>>>numbers in the whole numbers. As a result, the algorithm describing f >>>>is only required to be Ŝnite for those values of x for which f is >>>>deŜned. A function f with such an algorithm is in general called a >>>>partial function. A partial function f which is deŜned on all elements >>>>of the whole numbers is called a total function and is considered to be >>>>computable (or recursive). >>>> >>>>At this point, I believe we can start making some clear observations. >>>>First: the halting problem is only available for discussion if we a >>>>dealing with partial functions (which have algorithms that do not halt >>>>in Ŝnite time for some input values). >>>>Second: it appears to be your desire to discuss only total functions. >>>>Third: if we restrict ourselves to the total functions, discussing the >>>>halting problem is meaningless. >>>> >>>>A question that is relevent to the above: if we are restricting >>>>ourselves to total functions, is there a way to specify the algorithms >>>>of all total functions in such a way that there is no possibility of >>>>dealing with potentially partial functions? >>>> >>>>Before moving forward, do you have any comments on the above? Right now >>>>Iım just trying to set a framework for a detailed analysis, but if the >>>>basic framework is in dispute, I may need to adjust for that. >>> >>>The term to be deŜned is valid construction. Facts & FALSE -> anything. >>>> >>>>Agreed. I just wanted to make sure there were no objections before >>>>diving into the details. If the basic concepts to be deŜned in detail >>>>canıt be agreed on, then there isnıt much point in going further. >>>> >>>>For the moment, letıs allow functions to be n-ary for ease of notation. >>>>(It can be shown that we can restrict ourselves to unary functions, but >>>>they get messier.) >>>> >>>>Letıs start by deŜning primitive recursive functions These functions >>>>are guaranteed to be total functions and can be constructed by a Ŝnite >>>>number of applications of the following rules: >>>> >>>>1) f(x) = x+1 is primitive recursive >>>>2) f(x1,x2,...,xn) = m is primitive recursive where n and m >= 0 >>>>3) f(x1,x2,...,xn) = xi is primitive recursive where 0 < i <= n >>>>4) If g1, g2, .. gm, are primitive recursive and n-ary, and h is >>>>primitive recursive and m-ary then so is n-ary f deŜned as >>>> f(x1,x2,...,xn) = h(g1(x1,x2,...,xn),...,gm(x1,x2,...,xn)) >>>>5) For n>=1, if f is n-ary, g is (n-1)-ary, h is (n+1)-ary, and g and h >>>>are primitive recursive, then so is f deŜned by the following two rules: >>>>a) f(0,x2,x3,...,xn) = g(x2,x3,...,xn) >>>>b) f(x1+1,x2,x3,...,xn) = h(x1,f(x1,x2,...,xn),x2,...,xn) >>>> >>>>These rules appear (to my eye) to correspond with the deŜnition of a >>>>function guaranteed to halt you offered in another thread. >>>> >>>>Using these it is possible (though messy) to construct virtually all >>>>normal mathematical functions on the whole numbers. In particular, >>>>prime decomposition that will allow a number to represent a sequence of >>>>numbers by its prime decomposition. This enables us to formally get >>>>back to unary functions, if need be. >>>> >>>>Any comments at this point? The next question will be, do primitive >>>>recursive functions describe ALL total computable functions? >>> >>>nope >> >>Thereıs two questions, which one are you saying nope to? >>> >>>the 1st one, youıre supposed to be establishing the *next* question. >> >>Since there are only 5 rules for deriving primitive recursive functions, >> each one can be indexed based on what rules/functions are used to >>construct it. Consider one such indexing f0, f1, f2, f3, ... and let us >>construct a new function g0(x) = fx(x) + 1. Since fx can be formally >>considered unary, regarless of what n is for n-ary fx, and x determines >>the construction of f, g0(x) is deŜned on all x in the Whole Numbers. >>Moreover, we have included all partial recursive functions on our list >>f0, f1, f2, .... Therefore, g0(x) is a total function, it is >>computable, but it is not a primitive recursive function. By prepending >>g0(x) to the listing of primitive recursive functions, we can construct >>g1(x), g2(x), etc. Since there are multiple possible indexing schemes >>available for the primitive recursive functions, there are also multiple >>sequences of gi(x) available. >> >>Any issues with the above? >> > >I got no idea what rule 5 does. It looks like a step -1 for loop that pushes the >parameters into the 2nd parameter of the 2nd parameter recursively, making >a longer parameter list every iteration. >> >>Itıs a construction similar to f(0) = c, f(x+1) = g(f(x)). The idea is >>to deŜne f(0) as something known, and deŜne f(x+1) in terms of f(x). >>The parameter list doesnıt actually get longer. >> >> >>construct a new function g0(x) = fx(x) + 1 > >this is just diagonalisation all over again, f with godel x applied to its own godel number >with a modiŜcation. >> >>You are quite right. Now, does that invalidate the conclusion? >> >> >whatıs to stop me deŜning consistent p.r.f. where variable references are contextually free. >fx(x) = fx(y) for any x, y >> >>Those functions are described in construction 2, they are the constant >>functions. This has nothing to do with the validity or invalidity of >>the argument. >> >> >this stops dummy functions like the above that double usage the x in g0(x) >Iıve shown that getting a parameter x and using it for 2 arguments is >enough to change a total system to non halting system. >> >>We have not gotten to anything that does not halt. All that is being >>said is: a sufŜcient restriction to prevent functions that donıt halt >>also excludes some that do always halt. > ok, but how hard is it to exclude functions of type fx(x), theyıre the ones going > into inŜnite loops. what computation are they performing that canıt be > done some other way? > The functions fx do not contain inŜnite loops. Nor do the functions gi > built from them. The point was that the primitive recursive functions, > while guaranteed to halt, are not *all* of the functions that are > guaranteed to halt. The various functions gi are also guaranteed to > halt, but they were found using a diagonal-style argument, and are > therefore not primitive recursive. > Having said all that, MOST functions and operations that we would want > to perform would be primitive recursive functions, including things like > the addition function, subtraction function (which produces 0 for > negative results), multiplication, integer division, modular division, > exponentiation, etc. As long as the computations can be broken down > into the 5 rules applied to various primitive recursive functions, we > are good to go. > So far, there are no inŜnite loops, and everything is guaranteed to > halt. Itıs just that not everything that halts is primitive recursive. > The trick is to see if we can Ŝnd something that will include ALL > functions that halt, and still exclude those that donıt. If fx(x) is a construct that halts, then UTMs must be impossible. Because mUTM(mUTM) doesnıt halt, as weıve been through. If UTMs are not part of primitive recursive functions, then theyıre not complete anyway. Even so, what does g0(x) do? I still say you are entrenched in *names* of functions and not *what* they actually compute. Two algorithms can perform the same computation canıt they? Herc === Subject: Polygons With Angles Of Different k-gons I am wondering generally about irregular polygons which have angles each equal to that of different regular polygons. In other words, each interior angle is equal to (1 - 2/k)*180 degrees for a set of positive integers k. For example, we can have a 5-gon with the angle of an equilateral triangle, of a square, of a regular pentagon, of a regular hexagon, and of a regular 20-gon. Or, allowing dupicate angles, we can have a 4-gon with 2 angles of an equlilateral triangle, one angle of a square, and one of a dodecagon(12-gon). If we are allowed to adjust our polygonsı side-lengths as necessary, then which such irregular polygons can tile the inŜnite plane with congruent copies of themselves? Leroy Quet === Subject: Re: Polygons With Angles Of Different k-gons 3QLpj-NoP*NzsIC,boYU]bQ]Hıy<#4ga3$21: > I am wondering generally about irregular polygons which have angles > each equal to that of different regular polygons. > In other words, each interior angle is equal to > (1 - 2/k)*180 degrees > for a set of positive integers k. > For example, we can have a 5-gon with the angle of an equilateral > triangle, of a square, of a regular pentagon, of a regular hexagon, > and of a regular 20-gon. > Or, allowing dupicate angles, we can have a 4-gon with 2 angles of an > equlilateral triangle, one angle of a square, and one of a > dodecagon(12-gon). > If we are allowed to adjust our polygonsı side-lengths as necessary, > then which such irregular polygons can tile the inŜnite plane with > congruent copies of themselves? A convex polygon that tiles the plane must have at most six sides, so the only possible choices come from the Egyptian fraction representations of 1 with at most six terms, all <= 1/3. There are only Ŝnitely many such representations. In addition, it has to be possible to Ŝt the largest angle together with some combination of other angles around a single vertex; a combination of four angles is impossible (the four-angle combination maximizing the largest angle is 1/3+1/3+1/4+1/12, but all the Egyptian fractions I found had a term smaller than 1/12) so we must have three of these fractions 1/a + 1/b + 1/c = 1/2 where c is the largest term in the Egyptian fraction. So, it seems, this eliminates all but the following possibilities (in the distinct angle case; of course there are more if you allow repeated angles): 1/3 + 1/4 + 1/5 + 1/6 + 1/20 1/3 + 1/4 + 1/5 + 1/7 + 1/20 + 1/42 1/3 + 1/4 + 1/5 + 1/8 + 1/20 + 1/24 1/3 + 1/4 + 1/5 + 1/9 + 1/18 + 1/20 1/3 + 1/4 + 1/5 + 1/10 + 1/15 + 1/20 1/3 + 1/4 + 1/6 + 1/7 + 1/12 + 1/42 1/3 + 1/4 + 1/6 + 1/9 + 1/12 + 1/18 1/3 + 1/4 + 1/6 + 1/10 + 1/12 + 1/15 In each of these cases, the internal angles of the hexagon can be partitioned into two triples that each add to 360 (in the Ŝrst solution, consider the pentagon to be a degenerate hexagon with a 180 degree angle). If one can form a hexagon in which no two angles from the same triple are adjacent, and opposite pairs of edges have equal length, I think that would be enough to guarantee a tiling. If we Ŝx one edgeıs length and orientation, there are two remaining degrees of freedom in the other two edge lengths and two degrees of freedom needed to get the edge sequence to form a closed hexagon, so it looks like it may be possible in each case, but I havenıt worked out the details. -- David Eppstein http://www.ics.uci.edu/~eppstein/ Univ. of California, Irvine, School of Information & Computer Science === Subject: Re: (Almost)Consecutive-Integer Egyptian-Fraction Sum =1 > I was led to this question by considering (m+1)-sided polygons where > all but one of the sides are that of a k-gon, a (k+1)-gon, a > (k+2)-gon,..., an (k+m)-gon. Whooops. Should be (m+2)-sided polygons. Leroy > But I wanted the Ŝnal angle to be that of an n-gon, for some positive > integer n. > For example, > 1/3 + 1/4 + 1/5 + 1/6 + 1/20 = 1. > So, my question is, > which integers n are such that: > 1/k + 1/(k+1) + 1/(k+2) +....+1/(k+m) + 1/n = 1 ? > What is the sequence of such nıs? Is it in the EIS? > Leroy Quet === Subject: Question about Combinatorics iım searching the following solution there are T positions t1,t2, ... ,tT and L different colors c1,c2, ... ,cL there exists L^T different combinations. now i like to calculate the number of possibilities, where A colors are different. for example, how many combinations exists, where 3 entries are different? is there any closed solution aviable (maybe very simple, but i didnıt got the solution)? christoph / www.rune.ch === Subject: Re: math bibles euclid is Ŝne & rather dryly encyclopedic, although taht in a form that is not in the Britannica sense, but a better synthetic geometry is _Modern Pure Solid Geometry_ by N.Altshiller-Court -- you donıt acutally need the ŝat stuff as a prerequisite! as for calculus, Apostol uses the Leibnizian method of beginning with the integral, or the Whole (Enchilada .-) Knuth has never given any idea of the problem of the ŝoating-point algorithms & hardware (IEEE-755, -855, I think); they are inherently chaotic ... Chaos is the mother of Chronos! > Is there a classic bible of differential/integral calculus? Iım > looking for the book that is to calculus what Euclidıs Elements is to > geometry or, even better, Knuthıs TAOCP is to algorithm analysis -- --ils duces dıEnron! http://tarpley.net === Subject: Re: math bibles > Is there a classic bible of differential/integral calculus? Landau, Edmund (1877-1938). _Differential and Integral Calculus_ === Subject: Re: math bibles > Is there a classic bible of differential/integral calculus? Iım > looking for the book that is to calculus what Euclidıs Elements is to > geometry or, even better, Knuthıs TAOCP is to algorithm analysis -- > encyclopedic in scope, but with enough depth to be suitable for > learning/refresher in addition to academic reference. Iıve spent the > last few days searching Amazon, et al, but all the books I Ŝnd seem > to be either too application-focused, or copies of the same awful > modern textbooks. Anyone have any suggestions? > I also welcome suggestions of other biblical tomes in mathematics > and related Ŝelds. (I love books, and Iım always looking to add > another great one to my collection.) For example, Iım often surprised > how few people have sat down and spent a few evenings with George > Booleıs The Laws of Thought... For number theory, Disquisitiones Arithmeticae by C.F. Gauss. If your Latin is rusty, an English translation was published by Yale U Press. === Subject: Re: math bibles > Is there a classic bible of differential/integral calculus? Iım > looking for the book that is to calculus what Euclidıs Elements is to > geometry or, even better, Knuthıs TAOCP is to algorithm analysis -- > encyclopedic in scope, but with enough depth to be suitable for > learning/refresher in addition to academic reference. Iıve spent the > last few days searching Amazon, et al, but all the books I Ŝnd seem > to be either too application-focused, or copies of the same awful > modern textbooks. Anyone have any suggestions? > I also welcome suggestions of other biblical tomes in mathematics > and related Ŝelds. (I love books, and Iım always looking to add > another great one to my collection.) For example, Iım often surprised > how few people have sat down and spent a few evenings with George > Booleıs The Laws of Thought... The Bourbaki volumes were an impressive achievement when they were published, and still worth reading today. Any chance that someone will try to do what Bourbaki has done, updated for the 21st century? === Subject: Re: math bibles > Is there a classic bible of differential/integral calculus? Iım > looking for the book that is to calculus what Euclidıs Elements is to > geometry or, even better, Knuthıs TAOCP is to algorithm analysis -- > encyclopedic in scope, but with enough depth to be suitable for > learning/refresher in addition to academic reference. > I also welcome suggestions of other biblical tomes in mathematics > and related Ŝelds. Apostol for calculus. Herstein for undergrad abstract algebra. Royden for Real Analysis. Rudin has two analysis books - we used to call them Rudin and baby Rudin, but I guess you could call them the old & new testaments. Hardy & Wright for number theory. OıNan or Strang or Hoffman & Kunze for linear algebra. Marsden and Tromba for vector calculus. Ahlfors for complex analysis. Feller for probability. -- Gerry Myerson (gerry@maths.mq.edi.ai) (i -> u for email) === Subject: Re: math bibles > Is there a classic bible of differential/integral calculus? Iım > looking for the book that is to calculus what Euclidıs Elements is to > geometry or, even better, Knuthıs TAOCP is to algorithm analysis -- > encyclopedic in scope, but with enough depth to be suitable for > learning/refresher in addition to academic reference. > > I also welcome suggestions of other biblical tomes in mathematics > and related Ŝelds. > Apostol for calculus. Herstein for undergrad abstract algebra. > Royden for Real Analysis. Rudin has two analysis books - we used > to call them Rudin and baby Rudin, but I guess you could call > them the old & new testaments. Hardy & Wright for number theory. > OıNan or Strang or Hoffman & Kunze for linear algebra. Marsden > and Tromba for vector calculus. Ahlfors for complex analysis. Donıt forget Kelley for point-set topology, the Dunford-Schwartz trilogy for functional analysis, Stanley for enumerative combinatorics, and Spivak for differential geometry. > Feller for probability. === Subject: Re: math bibles > Apostol for calculus. Herstein for undergrad abstract algebra. > Royden for Real Analysis. Rudin has two analysis books - we used > to call them Rudin and baby Rudin, but I guess you could call > them the old & new testaments. Hardy & Wright for number theory. > OıNan or Strang or Hoffman & Kunze for linear algebra. Marsden > and Tromba for vector calculus. Ahlfors for complex analysis. > Feller for probability. You forgot logic, combinatorics, and topology -- Mitch Harris (remove q to reply) === Subject: Re: Euclidıs algorithm for quadratic sequence by support1.mathforum.org (8.11.6/8.11.6/The Math Forum, $Revision: 1.9 primary) id i4PJUdT22001; >Here is a problem that I have: >Given real constants a, b and eps > 0, I can quite easily Ŝnd the >smallest k >= 0 such that (a + b*k) mod 1 < eps, using Euclidıs >algorithm or a slight variation of it. Instead of requiring about 1/eps >steps if I just tried k=0, k=1 etc. sequentially, this takes only about >log (1/eps) steps, quite a difference (I need to solve this usually for >eps around 10^-15). >The problem is: I have real constants a, b and c, and I need to Ŝnd the >smallest k >= 0 such that (a + b*k + c*k^2) mod 1 < eps. c is very >small, about the same size as eps, and both are around 10^-15. I found a >method that takes about O ((1/eps)^(2/3) * log (1/eps)) steps - this >makes the problem solvable for me in a reasonable amount of time for eps >= 10^-15, but not for much smaller values like eps = 10^-18. Is there >any better algorithm for this problem known? Look at some of the work of Noam Elkies, speciŜcally http://arxiv.org/abs/math/0005139 === Subject: Re: Euclidıs algorithm for quadratic sequence >Here is a problem that I have: >Given real constants a, b and eps > 0, I can quite easily Ŝnd the >smallest k >= 0 such that (a + b*k) mod 1 < eps, using Euclidıs >algorithm or a slight variation of it. Instead of requiring about 1/eps >steps if I just tried k=0, k=1 etc. sequentially, this takes only about >log (1/eps) steps, quite a difference (I need to solve this usually for >eps around 10^-15). >The problem is: I have real constants a, b and c, and I need to Ŝnd the >smallest k >= 0 such that (a + b*k + c*k^2) mod 1 < eps. c is very >small, about the same size as eps, and both are around 10^-15. I found a >method that takes about O ((1/eps)^(2/3) * log (1/eps)) steps - this >makes the problem solvable for me in a reasonable amount of time for eps >= 10^-15, but not for much smaller values like eps = 10^-18. Is there >any better algorithm for this problem known? > Look at some of the work of Noam Elkies, speciŜcally > http://arxiv.org/abs/math/0005139 That will keep me busy for a while... === Subject: Re: Journal editors and reviewers, speak up you rely completely upon *argumentarium ad hominem*, as if there really were no mainstream mathematicians in the googolplex, or as if all of us amateurs (except for you) are just replaying our roles dıecole haute-grammaire (or what ever). it is sad that that group of your peers at the journal, would not give you a reason for their late refusal, although it is obvious that they got outside advice of your former illegible proofs of Fermatıs Last. were you one of the high-school abusers? > My assessment is that most mainstream mathematicians simply donıt > bother with talking in such a public forum where *anyone* can reply. > American high school type social scene because you failed so utterly > people who refuse to grow up, who relive high school nightmares out in > public by taking the role of the socially popular abusers, and joy in --ils duces dıEnron! http://tarpley.net === Subject: Re: Journal editors and reviewers, speak up > You know as well as I, Dr. Harris > Dr. Harris? Dr. Harris? Letıs not get carried away. > Doug I wouldnıt want to get carried away. No, Iıve gone that route before, and it led me astray. James probably doesnıt even read my posts anymore because of my past behavior. He has no reason to trust me. But that doesnıt mean I canıt point out to the rest of you some of the, umm, interesting patterns in your behavior. My previous post in this thread made the mild suggestion that there is, perhaps, a bias in the mathematical community against those who are not ofŜcial members of its club -- i.e., against those who do not hold doctorates in mathematics. I called James, Dr. Harris, employing the utmost irony: if he really were Dr. Harris, he wouldnıt be having these difŜculties, of course. I expected that some might disagree with me (of course weıre not an exclusive club, wink wink), but I found it extremely *interesting* that what raised a hackle was simply the string Dr. Harris It reminds me of a situation at my nephewıs Catholic kindergarten. Kids are allowed to bring in cake mix on their birthday, and the teacher helps them make cake. Any ŝavor you want . . . except devilıs food. I wonder if she crossed herself when she said devil. Or if she would cower and quail should passing rufŜans say Ni! to her. Mathematicians may think themselves too rational to tremble at mere words, so I say unto you all: Prof. James S. Harris, Ph.D. Director, Institute of Advanced Study Von Neumann Fine Professor of Mathematics Princeton University Did you make a plus sign? Oh, the horror of imagining James Harris to be one of us! Itıs not enough to actually do mathematics, oh no, it has to be published in a peer-reviewed journal. But wait! Itıs not enough to publish in a peer-reviewed journal -- the journal has to be reputable. Now what reputable journal is going to publish anything by someone without a Ph.D.? Not true you say? Oh, a graduate student at a prestigious university with a powerful advisor is also allowed to publish? Yes, yes, I know. Itıs not a matter of allowed. I know the party line. To be publishable in a reputable journal, work must be of a caliber that is rarely achieved by those without a doctorate. I was expecting this sort of reply, and I agree that it is plausible, but that is not the response I got. Instead: Dr. Harris?!?!? Aaaaaah! Horrors!!! But in reality, Dr. Harris would not be enough. The doctorate would have to come from a reputable university, right? And even if it did, it would have to be in the right Ŝeld . . . I mean, if James were to actually write a dissertation on something *original* (say Object Oriented Mathematics) which didnıt neatly Ŝt into one of our pigeonholes, well, that wouldnıt count, would it? Or, okay, suppose that James actually did stiŝe his creativity long enough to write a dissertation on something traditional and boring -- the cohomology of Banach algebras, say. Would that be enough? No! Weıd just make up some other criterion!!! Ha ha ha ha ha! And why would we do this? I know that you know the answer James. Youıre probably not reading this because you donıt want to hear it, but the reason is simply this: there is a conspiracy against you. Youıve rufŝed the feathers of too many eminent mathematicians, and theyıve decided to shut you out. You may wonder: is their control complete? No! Youıve proven that! There are some journals out there, apparently, that didnıt get the word. That eluded the gaze of the overseers. But all math journals are networked together in such a way that you donıt really have a hope of making it all the way to publication. But keep on trying. Doomed efforts are so noble. Better than clogging up these newsgroups, I suppose. Better than giving a conference talk no one will attend. Better than just giving up and starting a new life. -- Jim Ferry at U of Illinois, Urbana-Champaign, (no, I donıt educate) 2 email me l o o k up 1 row === Subject: Re: Journal editors and reviewers, speak up actually, I multiŝected. as to why he didnıt wait til they actually published -- or is it an e-journal, from which the paper was edited-out? -- he wonıt answer that, either, I guess. > Prof. James S. Harris, Ph.D. > Director, Institute of Advanced Study > Von Neumann Fine Professor of Mathematics > Princeton University > Did you make a plus sign? Oh, the horror of imagining James Harris to be > You may wonder: is their control complete? No! Youıve proven that! --ils duces dıEnron! http://tarpley.net === Subject: Re: Journal editors and reviewers, speak up > You know as well as I, Dr. Harris > Dr. Harris? Dr. Harris? Letıs not get carried away. > Doug > I wouldnıt want to get carried away. No, Iıve gone that route before, > and it led me astray. James probably doesnıt even read my posts anymore > because of my past behavior. He has no reason to trust me. > But that doesnıt mean I canıt point out to the rest of you some of the, > umm, interesting patterns in your behavior. My previous post in this > thread made the mild suggestion that there is, perhaps, a bias in the > mathematical community against those who are not ofŜcial members of its > club -- i.e., against those who do not hold doctorates in mathematics. > I called James, Dr. Harris, employing the utmost irony: if he really > were Dr. Harris, he wouldnıt be having these difŜculties, of course. > I expected that some might disagree with me (of course weıre not an > exclusive club, wink wink), but I found it extremely *interesting* that > what raised a hackle was simply the string > Dr. Harris > It reminds me of a situation at my nephewıs Catholic kindergarten. Kids > are allowed to bring in cake mix on their birthday, and the teacher helps > them make cake. Any ŝavor you want . . . except devilıs food. I wonder > if she crossed herself when she said devil. Or if she would cower and > quail should passing rufŜans say Ni! to her. > Mathematicians may think themselves too rational to tremble at mere words, > so I say unto you all: > Prof. James S. Harris, Ph.D. > Director, Institute of Advanced Study > Von Neumann Fine Professor of Mathematics > Princeton University > Did you make a plus sign? Oh, the horror of imagining James Harris to be > one of us! Itıs not enough to actually do mathematics, oh no, it has to > be published in a peer-reviewed journal. But wait! Itıs not enough to > publish in a peer-reviewed journal -- the journal has to be reputable. > Now what reputable journal is going to publish anything by someone without > a Ph.D.? Not true you say? Oh, a graduate student at a prestigious > university with a powerful advisor is also allowed to publish? > Yes, yes, I know. Itıs not a matter of allowed. I know the party line. > To be publishable in a reputable journal, work must be of a caliber that is > rarely achieved by those without a doctorate. I was expecting this sort of > reply, and I agree that it is plausible, but that is not the response I got. > Instead: > Dr. Harris?!?!? Aaaaaah! Horrors!!! > But in reality, Dr. Harris would not be enough. The doctorate would have > to come from a reputable university, right? And even if it did, it would have > to be in the right Ŝeld . . . I mean, if James were to actually write a > dissertation on something *original* (say Object Oriented Mathematics) which > didnıt neatly Ŝt into one of our pigeonholes, well, that wouldnıt count, > would it? Or, okay, suppose that James actually did stiŝe his creativity > long enough to write a dissertation on something traditional and boring -- the > cohomology of Banach algebras, say. Would that be enough? > No! Weıd just make up some other criterion!!! Ha ha ha ha ha! > And why would we do this? I know that you know the answer James. Youıre > probably not reading this because you donıt want to hear it, but the reason > is simply this: there is a conspiracy against you. Youıve rufŝed the > feathers of too many eminent mathematicians, and theyıve decided to shut you > out. > You may wonder: is their control complete? No! Youıve proven that! > There are some journals out there, apparently, that didnıt get the word. > That eluded the gaze of the overseers. But all math journals are networked > together in such a way that you donıt really have a hope of making it all > the way to publication. > But keep on trying. Doomed efforts are so noble. Better than clogging up > these newsgroups, I suppose. Better than giving a conference talk no one > will attend. Better than just giving up and starting a new life. That was rather long winded. What was your point? === Subject: Re: Journal editors and reviewers, speak up > All in all my analysis is that Usenet here is like, as I mentioned > before, an American high school, and maybe some of you recreated an > American high school type social scene because you failed so utterly > when you were kids. > Here you live the fantasy that youıre on the top of the heap socially, > and engage in insults and attacks on others as you may have received > attacks in the past. > For those not aware of the American high school social scene the movie > currently in wide release here called Mean Girls will give you > plenty of information. > Sadly, while it had much potential, Usenet has been taken over by > people who refuse to grow up, who relive high school nightmares out in > public by taking the role of the socially popular abusers, and joy in > trying to inŝict their emotional pain upon others: adults in body but > adolescents in reality as they never got past that stage, and still > canıt escape their scars. > James Often in error, but never in doubt. Harris Having failed miserably at mathematics, you now appear to be embarking on a career as a psychologist. However, you are dangerously close to practicing that profession without a license. See your own therapist! -- There are two things you must never attempt to prove: the unprovable -- and the obvious. -- Democracy: The triumph of popularity over principle. -- http://www.crbond.com === Subject: Re: Journal editors and reviewers, speak up >> You donıt seem to have noticed that the mainstream mathematicians >> youıve been attacking here (like Professors Magidin and Ullrich) >> also make use of those established and reputable outlets for their >> mathematical work. Itıs not difŜcult to Ŝnd published papers for >> the professionals who post here. Have you forgotten that *they* >> were the ones who encouraged you to try to get your work >> published? USENET is a hobby and a diversion for them, not the >> professional outlet *youıve* tried to make of it. > I donıt really recall either Arturo or David encouraging James to > submit his work to journals and waste the time of people doing real > work (which us folk posting here are typically *not* doing, at least > not while weıre posting). > I may be mistaken in my recollections. Perhaps I wasnıt clear enough in my writing. Arturo and David were mentioned just as examples of mainstream mathematicians in general. When I said *they* were the ones who encouraged you I meant some of the mathematicians who post here, not those two in particular. Actually, I donıt remember who in particular made those suggestions to James, but I do recall that several of the regulars here did so. -- Wayne Brown (HPCC #1104) | When your tailıs in a crack, you improvise fwbrown@bellsouth.net | if youıre good enough. Otherwise you give | your pelt to the trapper. e^(i*pi) = -1 -- Euler | -- John Myers Myers, Silverlock === Subject: Re: My paper passed peer review I have never submitted a paper for review. the question is, is it supposed to be a sort of hermetically-sealed effort of the reviewers, in a room-for-review, or do they take copies home in a pile & go through them, with liesurely reference to their other peers and non-human references? did Harris recieve *any* polite refutation/refusal, at all -- did he call the editor, a honky, or did the editor call him, a fermatiste? (although the advance factorization paper may not have acutally mentioned Pierre de, did it even have a recognizable hypothesis or abstract?) >As far as I know, the refutations sent to the journal under discussion >havenıt passed peer review. > Wouldnıt the proper thing to do have been to return the refutations > to the senders and suggest they submit the refutation as a formal > paper for future publication, subject to peer review? --ils duces dıEnron! http://tarpley.net === Subject: Re: Four people crossing a bridge Teabag wibbled: > > What % of the bridge can this ŝashlight illuminate? > It seesm to me that the returner need not cover 100% of the bridge on > most of his trips, saving hundreds if not thousands of seconds. > > any properly constructed bridge will have guard rail or hand rail > so that you can cross in pitch dark > You guys are picking apart the puzzle, which is something I love to > do, but you are also wanting to CHANGE the puzzle, and thatıs a Bozo > No-No. Iıll tell you what it is: the puzzle posits something apparently RealWorld, but it isnıt. This annoys me. Ask me something to do with JustNumbers, Ŝne, but start talking about bridges and ŝashlights and Iıll ask for more details about them. > 35 minutes, as Mu-Pi said. > Denny Crane. -- Am I in Bolton? === Subject: Re: Four people crossing a bridge 35 ... this really is a question for alt.stupidity === Subject: Re: Four people crossing a bridge > 35 ... this really is a question for alt.stupidity What is even more stupid is that you gave the answer days after it was Ŝrst posted. Did you copy it? === Subject: Re: Four people crossing a bridge So why donıt you smart ers from the Dorm Radio in the Basement of the Science Building post the ing solution... to the original puzzle as posed? Very few posters on this thread have even tried to post a solution. > Iım quite sure now that it was meant as a joke. > Of course it was meant as a joke. It helps to know from sci.math that > Clive Tooth is not an idiot, and it helps to know how often this puzzle > (used to) get posted to rec.puzzles... in the usual version, the obvious > answer, which is that the fastest person should accompany each of the > others one by one, is wrong. So whatıs particular about this version is if > you donıt look carefully you expect to use the same trick (to have the two > slowest go over together and neither of them come back), and you probably > say ha, think you can catch me out with this old chestnut? but of course > youıd be the one caught out. > And naturally the person who multiplied the times together was joking too, > in the spirit of the stupid puzzle, and someone caught that mistake too. === Subject: Re: Four people crossing a bridge > So why donıt you smart ers from the Dorm Radio in the Basement of > the Science Building post the ing solution... to the original > puzzle as posed? Very few posters on this thread have even tried to > post a solution. Itıs been posted several times: 35. === Subject: Re: Four people crossing a bridge > So why donıt you smart ers from the Dorm Radio in the Basement of > the Science Building post the ing solution... to the original > puzzle as posed? Very few posters on this thread have even tried to > post a solution. > Itıs been posted several times: 35. Yes, numbnuts, itıs been posted several times (by my count, 4)... the second time was by me, conŜrming the original solverıs solution, along with a hint as to why that was a solution. Suck me. Denny Crane. === Subject: Re: Four people crossing a bridge > So why donıt you smart ers from the Dorm Radio in the Basement of > the Science Building post the ing solution... to the original > puzzle as posed? Very few posters on this thread have even tried to > post a solution. > Itıs been posted several times: 35. There seems to be some confusion. A ŝashlight is simply US-English for the object called a torch in UK-English. -- Clive Tooth http://www.clivetooth.dk === Subject: Re: Four people crossing a bridge The Last Danish Pastry wibbled: > So why donıt you smart ers from the Dorm Radio in the Basement of > the Science Building post the ing solution... to the original > puzzle as posed? Very few posters on this thread have even tried to > post a solution. > Itıs been posted several times: 35. > There seems to be some confusion. A ŝashlight is simply US-English for > the object called a torch in UK-English. Ah, but one mustnıt confuse this kind of torch with a juggling torch. That would be a serious mistake. -- Am I in Bolton? === Subject: Re: Four people crossing a bridge >So why donıt you smart ers from the Dorm Radio in the Basement of >the Science Building post the ing solution... to the original >puzzle as posed? Very few posters on this thread have even tried to >post a solution. >>Itıs been posted several times: 35. > There seems to be some confusion. A ŝashlight is simply US-English for > the object called a torch in UK-English. As far as how language differences may cause variations in the outcome of the puzzle, we can burn that bridge when we come to it. --Bill -- The World Wide Web is the hugest vanity press in the history of the human race! http://billwilkinson.home.mindspring.com/index.html === Subject: Re: Four people crossing a bridge >> So why donıt you smart ers from the Dorm Radio in the Basement of >> the Science Building post the ing solution... to the original >> puzzle as posed? Very few posters on this thread have even tried to >> post a solution. >> Itıs been posted several times: 35. > There seems to be some confusion. A ŝashlight is simply US-English for > the object called a torch in UK-English. Hahaha quite good Clive, sounds like you have been studying the masters e.g. Kevin S. Wilson who trolled rec.puzzles extremely successfully in January 2002... This is a new departure for you though. Good luck. === Subject: Re: Four people crossing a bridge >So why donıt you smart ers from the Dorm Radio in the Basement of >the Science Building post the ing solution... to the original >puzzle as posed? Very few posters on this thread have even tried to >post a solution. >> Iım quite sure now that it was meant as a joke. >> Of course it was meant as a joke. It helps to know from sci.math that >> Clive Tooth is not an idiot, and it helps to know how often this puzzle >> (used to) get posted to rec.puzzles... in the usual version, the obvious >> answer, which is that the fastest person should accompany each of the >> others one by one, is wrong. So whatıs particular about this version is if >> you donıt look carefully you expect to use the same trick (to have the two >> slowest go over together and neither of them come back), and you probably >> say ha, think you can catch me out with this old chestnut? but of course >> youıd be the one caught out. >> And naturally the person who multiplied the times together was joking too, >> in the spirit of the stupid puzzle, and someone caught that mistake too. It looks like these two guys, together posted the solution: >It takes 43 minutes. >A and B cross the path ( 10 minutes) >A comes back. ( 11 minutes) >C and D cross the path. (23 minutes) >B comes back (33 minutes) >A and B cross the path (43 minutes) >> I think itıs implied theyıre trying to cross as quickly as possible. So >> why not 10 + 1 + 11 + 1 + 12 = 35 minutes? Merged into one: A and B cross the path ( 10 minutes) A comes back. ( 11 minutes) A and C cross the path. (23 minutes) A comes back (24 minutes) A and D cross the path (35 minutes) -- dgates@spamfreelinkline.com === Subject: Re: Balls Ioannis wibbled: > Lynn Kurtz [CapitalEth][EDouble Dot][Micro] .b3 .b9[EDo ubleDot].b9 > Of course, pool players frequently put spin on the cue ball (top, > bottom, side) which not only affects how it caroms off the target ball > but how it reacts to the cloth and rails. So itıs a bit (a lot) more > complicated than just elastic collisions. > --Lynn > You are right, of course. My use of in principle is almost always > guaranteed to be exaggerated :*) > Players also often strike the cue ball in such a way that it completely > bounces off the table and falls back. In principle all those actions can > be approximated, although it would be extremely difŜcult. The most recent snooker world championship featured one game where one player managed to get the ball off the table. How we laughed. I saw a roulette ball shoot out of the wheel and across the casino once. Donıt know what they did about the bets: I wasnıt playing, I was waiting for the poker tourney to start. -- Am I in Bolton? === Subject: Re: Balls > I saw a roulette ball shoot out of the wheel and across the casino once. > Donıt know what they did about the bets: I wasnıt playing, I was waiting > for the poker tourney to start. They should pay off on the bets for 0 and 00, and everybody else gets to ride for the next spin. === Subject: Re: Balls > In the game of snooker (see footnote) it is sometimes necessary to break > up a pack of touching red balls with the cue ball. Does the > unsolvability(?) of the three body problem mean that the player cannot > predict just where the cue ball will end up after such a shot? > I ask because commentators sometimes criticize a player for the way he > plays such a shot if the outcome is poor, especially in regard to the > position that the cue ball comes to rest in. My thought is that the > player can only trust to luck in such a situation. gravitating bodies, but wondered if it might also apply to three bodies interacting in other ways. -- G.C. === Subject: Re: Balls The original post, resurrected from 1997, asks -- essentially -- the jelly-bean problem: Is there a formula for determining the maximum number of jelly beans in a jar (or other shape). In an effort to win a contest at work, I spent considerable time and thought trying to solve this enigma. I failed miserably. I had ultimately decided that a straight line of jelly beans in one plane was a proper measure since any overlapping jelly beans would be in a different line, and I decided that I would take two measurements of the heigth, and two of the circumfrance, take an average of both measurements, and work out all the cross-multiplied possibilities, and take the average, or at least what seemed most reasonable, of the cubic volume calculations in unit-measures of jelly beans. I discarded my highest number, but it was closest to correct. So, apparently, I should have counted a line of jelly beans and its adjacent overlapping line AS ONE COMPACT LINE. Still, volume-wise, the depth of a cubic line is not quite two jelly beans, and I am unclear about how to measure or solve for the unseen depth of a cubic line of jelly beans in a jar. Very Respectfully, Ray Donald Pratt === Subject: Help with testing for nonlinearity Its been awhile since Iıve done stats work and I am very rusty. Any help would be greatly appreciated. Iım testing for linearity of some datasets against a time trend with a comparison of the correlation ratio and the correlation coefŜcient. Iım running into a few cases where my derived Eta-squared is less than my R-squared, which, by deŜnition, cannot be true, right? Iıve doubled over my Ŝgures and canıt Ŝnd where Iım going astray. My correlation coefŜcients look sound, and Iım deriving my Eta-squared as the SS(between groups)/SS(total) Any help/suggestions/observations would be fantastic! -FX === Subject: Re: Open letter to James Harris - Self-Publish > > Why donıt you self-publish your paper? > Excellent idea: he may seek tips from Mr Wolfram who > self-published his book. No, Mr. Wolfram was rich enough and inŝuential enough already to self-publish. James Harris would have to self-publish because nobody but an incompetent person would publish his work. === Subject: SimpliŜcation Assitance needed I havenıt used my math skills much at all for 20 years now, and I canıt even seem to do the problem below. Could one of you whizzes help me out on this? I think Iıve got my equation right, I just need to get the Theta (T) out on the right and get the equation in terms of N and P so I can calulate Theta, but canıt for the life of me remember the trig simpliŜcations. Here it is: / N / N cos(T-P) -N +1 ArcTan( -------- ) + ArcTan( ---------------- ) = 90 +P cos(T) / N sin(T-P) / Fred p.s. in case the multiple lines get out of whack, here it is on one line: ArcTan(N/cos(T)) + ArcTan( (N*cos(T-P)-N+1) / (N*sin(T-P)) ) = 90 +P === === Subject: Re: InŜnite Series: Summation [(-1)^(n-1)][(2+sin n)/sqrt n] -> Converge? > Does this series converge? By direct comparison to summation 1/sqrt n this > series is not absolutely convergent. But could it be conditionally > convergent? The absolute values of the terms do not approach zero > monotonically so ... ? Divide and conquer: sum[n=1 to inf]((-1)^(n-1)*2/sqrt(n)) converges conditionally (standard alternating series test); sum[n=1 to inf]((-1)^(n-1)*sin(n))/sqrt(n) also converges conditionally, for a slightly more subtle reason (Dirichletıs Test). [Rest can be skipped] The second series directly: Denote x=pi-1, then sin(n*x) = (-1)^(n-1) * sin(n), so the second series is sum[n=1 to inf] sin(n*x)/sqrt(n) and we manipulate the partial sums (N >= 2) sum[n=1 to N] sin(n*x)/sqrt(n) = cos(x/2) - cos((N+1/2)*x)/sqrt(N+1) + 1/(2*sin(x/2)) * sum[n=1 to N-1] A(n) where A(n) = (1/sqrt(n) - 1/sqrt(n+1)) * cos((n+1/2)*x) (check it out; itıs called summation by parts). The last sum (extended to inŜnity) is convergent absolutely, and the initial terms converge as N goes to inŜnity. Oh, and sin(x/2) is different from 0. === Subject: Re: Can the deduction theorem be used recursively? >> No, Godelıs Completeness Theorem is the converse: >> logically valid wffs are theorems. I meant iff. >> > [...] it depends on who you ask > Only if you ask someone who is clueless [...] (Chris Mentzel) > :-) > Introduction to Mathematical Logic, Mendelson 1964, pg. > 68, Godelıs Completeness Theorem: In any Ŝrst order predicate > calculus, the theorems are precisely the logically valid wffs. > Idiot, of course this is a *corollary* of G.9adelıs Completeness Theorem. Maybe so, but thatıs not how Mendelson describes it (as you can see.) I looked it up on the internet (the Ŝrst time Iıve actually read much about it - Iıve seen it but never got into it) and saw that it was different than what Mendelson says (=> vs. <=>) so I opted for Mendelson (for obvious reasons) and said It depends on who you ask. Mendelson is clueless?!?!? > I knew about the resistance that I quoted earlier > Right. Never forget: _The resistance_ actually PROVES that you are > right, that you MUST BE right! Well actually yeah. You know why? They try so hard to prove me wrong but fail! They foam at the mouth at the possibility that Iıve developed something new, which might add legitimacy to my observations about BS in CS (BoguS Computer Science publications). So they try like hell to Ŝnd someone else who has developed a Program Synthesis system or axiomatized the Theory of Computation - and thatıs exactly what I need. When they come up empty-handed or drag out nonsense like the Boyer-Moore paper (not a single character of which is program output), it conŜrms that Iım the only one whoıs done it. What better reafŜrmation than someone who is DYING to prove me wrong falling ŝat on their face? The funniest part is when I talk about something that I have spent very little time with (other than looking it up on the internet because someone posted something about it and making a quick response to their post) like some part of Set Theory or Proof Theory, and make a mistake, and they go crazy! Charlieıs stupid, Charlieıs a liar, Charlieıs paperıs no good. And my paper has nothing to do with Set Theory or Proof Theory! LOL I guess thatıs easier than actually reading it and saying something about its contents. :-p > from The Mystery of the Aleph: > > Conservative thinkers sought to restrict novel ideas, since these new > point of view, he should have been shaped in their image, and had no > right to challenge his teachersı philosophy. Cantor believed that > their arbitrary restrictions impeded the growth of the Ŝeld. He gave > many examples of mathematical ideas that never would have had a chance > to succeed and evolve if their proponents had encountered the kind of > opposition he faced. > > Right. First came CANTOR - and now you. I see. Well, there is a lot of similarity, actually. The resistance without addressing the issues, the incompleteness connection. I even read that Cantor published some of his work himself. I guess some things never change. Charlie Volkstorf Cambridge, MA > F. === Subject: Re: Can the deduction theorem be used recursively? >> >> No, Godelıs Completeness Theorem is the converse: >> [all] logically valid wffs are theorems. >> > I meant iff. Itıs still wrong. Look, Charly, Iıve read G.9adelıs paper, I KNOW what he has proved in it. > Introduction to Mathematical Logic, Mendelson 1964, pg. > 68, Godelıs Completeness Theorem: In any Ŝrst order predicate > calculus, the theorems are precisely the logically valid wffs. > > Mendelson is clueless?!? No. See D. Ullrichıs comment: That iff is traditionally broken into two parts, one the soundness and one the completeness. The soundness theorem is trivial, the completeness isnıt. The iff is indeed true; if someone called that Godelıs Completeness Theorem it would be because the completeness, which Godel proved, is the non-trivial half. (David Ullrich) And in my own words: FIRST you have to prove that the system is consistent - thatıs the easy part. And then you have to prove that it is complete - thatıs the hard part. G.9adel was THE FIRST to present a proof for that, concerning FOPL. predicate calculus, the theorems are precisely the logically valid wffs. F. === Subject: Re: Can the deduction theorem be used recursively? > > And formal systems giving sound and complete axiomatizations > for FOL with MP as the only inference rule also exist. > > You really think you do a lot for your (giggle) status as a genius > by continuing to dispute something this elementary? > > I donıt have to dispute that. Godel proved in 1931 that there is no > sound and complete axiomatization for FOL. > > You appear to be confused about what Godel has shown. In fact, Godel > proved the (semantic) *completeness* of FOL -- in 1930 IIRC. He proved > the incompleteness of *arithmetic* (that is, of any consistent, > recursive axiomatization of it) in 1931. Perhaps you are also > confusing the sense in which FOL is complete with the sense in which > arithmetic is not. They are not the same. > I think the question is that of terminology. I thought he was > referring to completeness in the sense that is denied by Godelıs > Incompleteness Theorem, rather than in the sense that it is conŜrmed > by Godelıs Completeness Theorem. But, see, you really shouldnıt have, because it is impossible -- simply *by deŜnition*, not because of Godelıs theorem -- to have a sound and complete axiomatization of FOL in that sense of complete. You didnıt realize that. Do you see why that might lead one to think you donıt understand the subject matter? > You seem to be saying that calling the former a refutation of a sound > and complete axiomatization for FOL is deŜnitely wrong, Confused might be more appropriate than wrong. > although I have heard it described with so many different terms that I > am a little surprised to hear that. Perhaps you can explain why there > is such a lack of standardization of terminology in the literature, > but there is a standard that is being violated here. But that terminology is completely standard. And really, there is no problem here. Like many terms with two meanings, occurrences of complete are wholly disambiguated by context -- though, of course, you have to understand the contexts. > What are you babbling about here? Name something that Hilbert > said was so that turned out to be false. > > There are absolutely no unsolvable problems. > > Hilbert explicitly takes the solvability axiom to be an unproved but > important methodological conviction that motivates the mathematical > researcher. He *hoped* it was true, and perhaps believed it was (in > 1900), but he never asserted it with the sort of dogmatic certainty your > paraphrase above suggests. > Believe me that I am not the source of the translation. I know of at > least 6 sources for that quote. Yes, one bad translation and 5 copies. Weıll no doubt see more because of Google. > Please complete the following by Ŝlling in the blank with an English > sentence: When Hilbert became an honorary citizen of K.9anigsberg, he > gave a lecture, published in 1931, in which he said, ___. Instead of > the foolish ignorabimus, our answer is on the contrary: We must know, > We shall know. F.9fr uns gibt es kein Ignorabimus, und meiner Meinung nach auch f.9fr die Naturwissenschaft .9fberhaupt nicht. For us there is no Ignorabimus, and in my opinion none at all in the natural sciences. Both for us [mathematicians] and in my opinion pretty clearly indicate this was a methodological principle, perhaps even a reasonable belief, but not something Hilbert thought had been (or even perhaps could have been) conclusively demonstrated. The translation you cited is obviously very poor. > I am wondering if anyone has been wise enough to point out that the > set of axioms should be Ŝnite - which would preserve the analogy with > programming languages Why on earth should *that* be a constraint on what counts as an axiomatic system? Programming languages are a relatively recent invention. Clear instances of inŜnite axiomatic systems were around some 50 years prior to the development of the Ŝrst programming languages. > Actually, ZF is not even a true axiomatic system,... > > Youıre quite wrong about that. You donıt get to decide what counts as > an axiomatic system (unless of course you arenıt interested in > conversing with the mathematical community). > I thought mathematicians were allowed to make judgments. This isnıt a matter for judgment. What counts as an axiomatic system at this point in time is simply a matter of deŜnition. You can decide not to make use of the deŜnition if you donıt like it for some reason, but the fact is that it is now pretty much universally accepted within the mathematical community, and the fact is that that deŜnition permits axiomatic theories with inŜnitely many axioms. The *proper* response for you, with your strictly Ŝnitistic leanings, is *not* to try to say that axiomatic theory doesnıt in fact mean what it universally does, but rather that the only theories that you think are philosophically legitimate have only Ŝnitely many axioms. > Offhand (speculating), I would say that ZF is probably not Ŝnitely > axiomatizable because of the Axiom of Foundation. > > Wrong again, provably so. > > (I have not pursued a proof, and would welcome an on-line source.) > > Google non-well-founded set theory. > I donıt see a proof off-hand, and would still like to. What about ZF > gets in the way, then? Well, in a nutshell, the fact that (due to the replacement schema) it has inŜnitely many independent axioms. > The rest of ZF looks, prima facie, easily Ŝnitely axiomatizable. > > Er, how would you suggest revising the replacement schema? > As with any axiom schema that substitutes any particular formula for a > variable, we simply need axioms that deŜne the set of formulas. I havenıt a clue as to what you think you are suggesting. > (What does Er mean?) Same as welllll or ummmmm... > Thus we have the awkward situation in which a system tells us both > what is and what is not. > > A confusing and misleading remark; been reading Sein und Zeit? ;-) The > only sense I can charitably make of it is that ZF entails both that > certain sets exist and also rules out the existence of certain purported > sets (non-well-founded ones, for instance, or ones containing members of > unbounded rank). > You got it! > Nothing awkward about that. > How do you generate legitimate sets when some axioms say what are sets > and others say what arenıt? Err, wellll, ummm, assuming by generate you mean prove the existence of, suppose I give you some axioms about what ducks are: Ducks are birds. Ducks have oily feathers. Ducks have a rounded beak. Ducks have webbed feet. Ducks quack. Then you come along, and having never seen a duck, but lots of dogs, ask whether ducks have fur, bark, and have teeth. Accordingly, I add some axioms about what ducks arenıt: NO ducks have fur. NO ducks bark. NO ducks have teeth. Now, didnıt that qualiŜcation about what ducks arenıt help us to better understand what ducks are? It wasnıt contradictory at all to say what is not in duck theory, right? Same with set theory. > In ZF, however, we know that there are in fact formulas that do not > deŜne legitimate sets. The axiom of foundation prohibits them and we > must be careful not to consider such a formula as deŜning a set (to > avoid a paradox.) But axiomatic systems have no mechanism to generate > both what is and what isnıt (a set), or formulate a reaction to the > potential of there being an inconsistency. The mathematician has to > be careful not to make that mistake. That is why I say that ZF is not > a true axiomatic system, since in practice we do need to take > additional steps to avoid that potential inconsistency. > An axiomatic system, by its nature, tells us only what is. > > It just ainıt so. You are making stuff up that contradicts standard > deŜnitions. This is not a good way to make headway in the mathematical > community. > An axiomatic system is a way to generate theorems (an r.e. set.) Well, thatıs one sort of operational way to look at it. > And in ZF the theorems are really just statements that generate > allowable sets. You can use them to *prove* that certain sets exist, but they donıt generate sets. They describe them. > Except that some theorems say what is NOT a set. Just as some axioms of duck theory say what a duck is NOT. You think this is some sort of problem. It isnıt. Trust me. > That goes against the grain of generating an r.e. set (of sets.) This thing about axioms generating sets might be the source of your confusion, though I confess I donıt know what that confusion is. > We canıt say that the result of applying a rule to theorems generates > allowable sets. I donıt know what this means. > (Iıd rather be right than popular.) Alas, currently you are neither. > Typically (at least, in all the texts I can think of) a formal theory is > deŜned in such a way that the question of whether or not a sequence of > sentences is a legitimate proof from the set A of axioms of the theory > is completely independent of issues of decidability. But, of course, if > you want to be able to *tell* when something is a proof from A, then A > in general has to be not merely r.e. but fully recursive. > I tend to agree, What do you mean you *tend* to agree? Thatıs like saying you tend to agree that, say, the complement of a recursive set is recursive. > although typically you use an axiomatic system to generate proofs, not > to decide if a particular thing is a proof. How axiomatic systems are typically used is an empirical matter, one whose relevance is far from clear, but, be that as it may, you canıt very well *use* an axiomatic system to generate proofs if you donıt have a sureŜre way of deciding whether or not a certain sentence that you need at some step in the proof is an axiom. Either way, you need the axioms to be recursive. R.e. wonıt cut it. > So having an inŜnite number of axioms is even worse than I said. Youıve yet to identify a problem, let alone something even worse. If the axioms are recursive, there isnıt one. > I admittedly have yet to give it a close look, but your confusion > over a number of fairly elementary points here raises suspicions > about the rather grandiose claims you make for your theory of > computation. > All I see is a potential issue regarding terminology, and some > disagreements over what constitutes a reasonable axiomatic system. Unfortunately, these are not mere issues or disagreements. There is a good deal of confusion on your part. > In any case, I would caution you to not draw too many conclusions > about a paper that you havenıt read yet. (We have enough of that here > already.) :) I have drawn no Ŝrm conclusions about it. Rather, as noted earlier, your confusions over numerous elementary points of mathematical logic and set theory simply raise suspicions, though at this point for me, very strong ones. It is quite inconceivable to me that your work could have the virtues and signiŜcance you claim for it when you are so unclear about such elementary matters. These doubts are strengthened when you expend a lot of energy defending your mistakes instead of acknowledging them and moving on. Chris Menzel === Subject: Re: Can the deduction theorem be used recursively? > How can anybody take mathematical logic seriously? Goedel proved his > incompleteness theorem, and he *also* proved his completeness theorem. Tarski > proved the undeŜnability of truth, and he *also* gave a deŜnition of truth. Set theorists seem content with coming up with silly names for technical concepts. I mean, come on, pre-mouse, universal weasel, handgranade, ... Not that I mind, though. -- Aatu Koskensilta (aatu.koskensilta@xortec.Ŝ) Wovon man nicht sprechen kann, daruber muss man schweigen - Ludwig Wittgenstein, Tractatus Logico-Philosophicus === Subject: Re: Can the deduction theorem be used recursively? > No itıs not why you said it was impossible! Youıre lying about > what you said - when you do that you should probably at > least not quote what you said. You know why I said something and Iım a liar because I denied the real reason why I said it?? Terrible! > You said it was impossible because of Godelıs Incompleteness > Theorem. (Itıs not clear to me which is the more charitable > assumption here: youıre lying about what you said, or you > think that there exists P such that neither P nor ~P is a > theorem of FOL is a proof of Godelsı Incompleteness Theorem.) Yeah, right. Sounds like a proof to me. > Excellent point. Or in any case it _would_ be an excellent point > if exhibiting ignorance was the same thing as boldly going where > no man has gone before. Well, what do you expect from a stupid guy like me? >> No, the axioms of ZF have nothing >> to do with deŜning what constitutes a wff. >Youıve got half of it. Now see if you can understand the second half: > If they did, then you wouldnıt need axiom schemata. > Youıre catching on, omitting the bit I was replying to, where > you said that the axioms of ZF come in two parts, the ones > that deŜne what a wff is and the other ones. I omitted something? Oh, so Iım a liar again. Oh, I see. Charlieıs a big liar. Thatıs 2 or 3 times in one message. He lies about why he says things and he omits things in a message. Gad! Not only stupid, but a big liar, too. > Again, fascinating technique. You say A includes B, I > say no it doesnıt, and you say Iıve got half of it. Well, if you really want to know: ZF has nothing to do with deŜning what a wff is since it doesnıt, so thatıs the Ŝrst half. The second half is that if it did, then instead of axiom schemas you would have axioms for both what constitutes a wff and for the sets deŜned from them. Or am I just trying to talk my way out of lie # 3? (or is it # 4?) > The deŜnition of a wff has nothing to do with axioms. The > deŜnition of a wff is part of the deŜnition of a _language_; > the axioms of set theory are wffs _in_ that language. Itıs back to the principle of processes. Iım talking about whatıs needed a process that deŜnes (generates) the wffs, combined with the process that takes those wffs and deŜnes sets from them. All of that could be done with axioms, rather than axiom schemata. > Nobodyıs called you stupid for saying things contrary to whatıs > been published. People have called you stupid Oh, itıs plural now? Must be, then. > for saying things > that are _false_ (and well-known to be false) - the way you go > on about how youıve done things that nobodyıs done, and > the way you reply to comments has something to do with > that. (whatever it says.) No need to waste time thinking about that! Ok, reality check: You confuse reading and memorizing certain theorems with intelligence and creativity. You spend your life memorizing. I spend my life creating. To each his own. Charlie Volkstorf Cambridge, MA > Anyway, Chris has already given a big hint as to _why_ > ZF is not Ŝnitely axiomatizable (which is not quite the > same as a hint regarding how one actually proves > that). So Iıll just call you stupid for saying that you > suspect that the axiom of foundation has something > to do with the fact that ZF is not Ŝnitely axiomatizable: > Thatıs _one_ axiom, not an axiom scheme, so itıs > equisitely hard for me to see how it could have > anything to do with it. (Every nonempty set x > has an element y such that x and y are disjoint.) >Charlie Volkstorf >Cambridge, MA >> ************************ >> >> David C. Ullrich > ************************ > David C. Ullrich === Subject: Re: Can the deduction theorem be used recursively? > Godel proved in 1931 that there is no sound and > complete axiomatization for FOL. (Charlie-Boo) >> >> You really donıt have any understanding of _any_ of this stuff, >> right? the wrong completeness. Now everything you ever spouted out is true, vindicated, authenticated. You Ŝnally have your ironclad proof that Charlie is a dumb-ass who doesnıt know anything about anything. He misused the word completeness. You put him to shamw. Giggle. Gaggle. Guggle. Gafŝe. Can we all say that together now, children? Can you say Goggle - Gaggle - Guggle - Gafŝe? Maybe if you studied Mathematics and Logic for 10 years you could learn to be say it too! Gaggle Guggle Giggle Gafŝe Gufŝe Goggle # of Posts: 534 # of Ideas Presented: 0 # of Problems Solved: 0 # of Systems Developed: 0 # of Cut & Paste from famous books: 534 LOL You are pitiful. You are so jealous of the smart people. COMPLETE canıt be ambiguous the famous guys put it in the titles of they Ŝrst published it it didnıt exist yet! LOL Or maybe theyıre using it in the same way. Who cares? What difference does it make? Youıre such a fame-worshiper. You canıt even judge if a word is ambiguous or not you ask the famous people. I come up with more ideas in a day than youıve ever posted in your entire life. Of course I make mistakes Iıve posted hundreds of ideas. Naturally some of them are going to be misinterpretations, misreadings. That has nothing to do with intelligence or creativity. Those are just stupid little slip-ups. I thought he meant completeness as in Godelıs Incompleteness Theorem, not Godelıs Completeness Theorem. So what? Itıs just a word - a term. Does that have anything to do with intelligence? Creative ability? Or, for that matter, honesty or maturity? Of course not. But to you, famous words, famous authors, famous titles - are your security blanket. Your fetish. Your self-reassurance. Your friends. The people you bond with. Your weapons. Your life. The only way you would ever make a mistake is when you misspell someoneıs name as you type in their work. Frege itıs not your work. Itıs not you. Those people donıt really exist. Theyıre mostly dead. You arenıt really Frege. Itıs all a dream. Pretend. Make believe. Fame. Prestige. Reputation. They donıt rub off, Frege. Quoting a famous person doesnıt make you famous. Quoting a famous person doesnıt make you smart. Youıre a secretary. A photocopy machine. A carbon copy. A blurry, faded carbon copy of a man. C-B >> > I assumed you meant complete in the sense of every sentence being > provable or refutable > >> Right. In other words, you didnıt know what sound and complete >> axiomatiziation for FOL means. >> > No, I donıt know what you mean when you use an ambiguous term like > complete. > > G.9adel, Kurt, Die Vollst.8andigkeit der Axiome des logischen > Funktionenkalk.9ŝs, Monatshefte f.9fr Mathematik und Physik, > 37: 349-360, 1930. > Henkin, Leon, The Completeness of the First-Order Functional > Calculus, Journal of Symbolic Logic, 14: 159-166, 1949. > Right, G.9adel and Henkin used ambiguous terms in the titles of their > papers. _Giggle_ :-) > > rather than in the sense of the theorems being logically valid > (assured by Godelıs Completeness Theorem.) > >> No, Godelıs Completeness Theorem is the converse: >> logically valid wffs are theorems. >> > [...] it depends on who you ask > Only if you ask someone who is clueless [...] (Chris Mentzel) > :-) > Introduction to Mathematical Logic, Mendelson 1964, pg. > 68, Godelıs Completeness Theorem: In any Ŝrst order predicate > calculus, the theorems are precisely the logically valid wffs. > Idiot, of course this is a *corollary* of G.9adelıs Completeness Theorem. > FIRST you have to prove that the system is consistent - thatıs the easy > part. And then you have to prove that it is complete - thatıs the hard > part. G.9adel was THE FIRST to present a proof for that, concerning FOPL. > In any Ŝrst order predicate calculus, the theorems are precisely the > logically valid wffs. >> >> You should really drop all this soon - each post is more >> hilarious than the last. >> > I have nothing against being entertained. More importantly, it is > serving one of my original objectives: to get into the heads of the > people so entrenched in the old boyıs club where reputation takes > the place of technical analysis. > Right, you already got in my head as a typical usenet crank. > I am seeing a couple of things. > Sure... Much more than ordinary persons, thatıs for sure. :-) > I found out a long time ago that journals like authors who validate > existing dogma. > Ehrr? > I knew about the resistance that I quoted earlier > Right. Never forget: _The resistance_ actually PROVES that you are > right, that you MUST BE right! > from The Mystery of the Aleph: > > Conservative thinkers sought to restrict novel ideas, since these new > point of view, he should have been shaped in their image, and had no > right to challenge his teachersı philosophy. Cantor believed that > their arbitrary restrictions impeded the growth of the Ŝeld. He gave > many examples of mathematical ideas that never would have had a chance > to succeed and evolve if their proponents had encountered the kind of > opposition he faced. > > Right. First came CANTOR - and now you. I see. > But now I am seeing even more. > Sure... > Itıs not just to reafŜrm what they > teach. Quoting others is the only thing that they know. If you try > to make a point that questions the validity of an existing school of > thought, it involves actually understanding what the existing system > is doing, what it is trying to accomplish, and what is wrong. Itıs > just so much easier to quote other people. > Indeed! :-) > The problem isnıt completely psychological. > > Iım not so sure about t h a t. === Subject: New (?) Technique for Drawing a Tetrahedron Iıd Ŝgured-out that isometric drawings were the same as taking an extreme telephoto lens to your subject (or looking at the stars) in my mechanical drawing class in junior high. recently, I also realized that you donıt have to go with making all three XYZ coords equal, at the same apparent angle of view. yesterday, while making my poster for a poster-session at UCLA, a simple diagram of a tetrahedron, used to represent an airplane for a weight & balance determination, I realized that itıs simple, isometrically, to exactly represent any tetrahedron, just by using a circle to represent the circumsphere of the tetrahedron; see, How? actually, this is the perfect place to use the dual terminology, tetra-asteron, since we afŜx the 4 points to the circumsphere, or to the celestial sphere. --ils duces dıEnron! http://tarpley.net --Give Earth a Trickier Dick Cheeny -- out of ofŜce, after gigayears! http://www.benfranklinbooks.com/ http://members.tripod.com/~american_almanac http://www.wlym.com/pdf/iclc/HowTheNation.PDF http://www.rand.org/publications/randreview/issues/rr.12.00/ http://www.rwgrayprojects.com/synergetics/plates/Ŝgs/plate02. html === Subject: yıı x^2 + 2yı x - y^3 = 0 ? Does anybody have any suggestions on how to Ŝnd an analytic solution to yıı x^2 + 2yı x - y^3 = 0 ? === Subject: Re: smallest disk covering a set of points > A = { (x,0) in Q^2 : x > 0 and x^2 < 2 }. > Itıs not completely self explanatory. You seem to be missing the fact > that the center of the disk must be a point belonging to the space under > consideration (in this case, Q^2). This is an unnecessary complication in my view, as Iıve already stated. Since Q^2 is a subset of R^2, Iım quite happy to accept an R^2 solution. > Look at the set A above, and think of it as a subset of R^2. That set > has a minimum covering disk in R^2, namely the disk centered at > ( sqrt(2)/2, 0 ) with radius sqrt(2)/2. Agreed. This would be my solution. > However, there is no disk in Q^2 that is centered at sqrt(2)/2, since > sqrt(2)/2 is not in Q. Therefore, the best you can do in Q^2 is to > choose a point with rational coordinates that is close to > ( sqrt(2)/2 , 0 ) and then choose a radius slightly larger than sqrt(2)/2 > in order to cover the whole set. Fair enough. > The closer the center is to ( sqrt(2)/2 , 0 ), the smaller the radius can > be. There is no closest point to the desired center in Q^2, and > therefore there is no smallest radius. Hence, no MCD in Q^2. Do you have proof that there is no Œclosestı point? Bear in mind that Iım not familiar with the restrictions of the coordinate system. Iım starting to get the picture that youıre arguing about the word Œminimumı... speciŜcally that there are two Œclosestı points in Q^2 to the point (sqrt(2)/2,0), thus two discs of minimum radius, therfore no MINIMUM covering disc. If thatıs what youıre trying to point out, why didnıt you just point it out in the Ŝrst place? Sheesh :> -- Corey Murtagh The Electric Monk Quidquid latine dictum sit, altum viditur! === Subject: Re: smallest disk covering a set of points > >> A = { (x,0) in Q^2 : x > 0 and x^2 < 2 }. > >> Itıs not completely self explanatory. You seem to be missing the fact >> that the center of the disk must be a point belonging to the space under >> consideration (in this case, Q^2). > This is an unnecessary complication in my view, as Iıve already stated. > Since Q^2 is a subset of R^2, Iım quite happy to accept an R^2 solution. Not every metric space can be realized as a subset of R^2. Besides, the whole point of this discussion is to realize that R^2 has special properties that make it possible to deduce a solution in that speciŜc context, even though similar solutions may not exist in arbitrary metric spaces. You are just attempting to sweep the special properties of R^2 under the rug by pretending that all metric spaces share the same properties. They donıt. >> Look at the set A above, and think of it as a subset of R^2. That set >> has a minimum covering disk in R^2, namely the disk centered at >> ( sqrt(2)/2, 0 ) with radius sqrt(2)/2. > Agreed. This would be my solution. That is the solution to a different problem. It is not a solution to the problem that was posed. >> However, there is no disk in Q^2 that is centered at sqrt(2)/2, since >> sqrt(2)/2 is not in Q. Therefore, the best you can do in Q^2 is to >> choose a point with rational coordinates that is close to >> ( sqrt(2)/2 , 0 ) and then choose a radius slightly larger than sqrt(2)/2 >> in order to cover the whole set. > Fair enough. >> The closer the center is to ( sqrt(2)/2 , 0 ), the smaller the radius can >> be. There is no closest point to the desired center in Q^2, and >> therefore there is no smallest radius. Hence, no MCD in Q^2. > Do you have proof that there is no Œclosestı point? Bear in mind that > Iım not familiar with the restrictions of the coordinate system. Consider a covering disk for A that is centered at the point (p,q) in Q^2. If q is nonzero, then we note that the point (p,0) is also in Q^2 and there is a covering disk centered at (p,0) that is smaller than any covering disk centered at (p,q). Therefore we only need to consider rational points on the x-axis as candidates for the center of a covering disk. The closer p is to sqrt(2)/2, the smaller the covering disk centered at (p,0) can be. But p cannot coincide with sqrt(2)/2, since p is required to be rational. By the density of the rationals, there is a rational pı that lies between p and sqrt(2)/2, and the covering disk centered at (pı,0) can be smaller than any covering disk centered at (p,0). Hence, no smallest covering disk is possible, for the same reason that there is no rational number that is closest to sqrt(2)/2. > Iım starting to get the picture that youıre arguing about the word > Œminimumı... speciŜcally that there are two Œclosestı points in Q^2 to > the point (sqrt(2)/2,0), thus two discs of minimum radius, therfore no > MINIMUM covering disc. Two closest points? Name one of them. > If thatıs what youıre trying to point out, why didnıt you just point it > out in the Ŝrst place? Sheesh :> Because there most certainly are *not* two closest points. There are no closest points whatsoever. Sheesh. -- Dave Seaman Judge Yohnıs mistakes revealed in Mumia Abu-Jamal ruling. === Subject: Re: smallest disk covering a set of points > ) So my approach was to Ŝnd an MCD in RxR and then pick a smallest MCD in > ) QxQ that contains the MCD of RxR - it neednıt have the same radius or > ) centre. > There are discs in RxR that donıt have a smallest covering disc in QxQ. > (That is, for any covering disc you supply, I can Ŝnd a smaller one.) > Worse, for any number in R thatıs not in Q, the set of larger numbers in Q > doesnıt have a smallest member. (i.e. itıs open-ended.) Whatıs the smallest real number greater than 1? :> -- Corey Murtagh The Electric Monk Quidquid latine dictum sit, altum viditur! === Subject: Re: smallest disk covering a set of points )> Worse, for any number in R thatıs not in Q, the set of larger numbers in Q )> doesnıt have a smallest member. (i.e. itıs open-ended.) ) ) Whatıs the smallest real number greater than 1? :> Sorry, I should have said Œthe set of not-smaller numbersı, which in this case happens to be exactly the same, but only because the number R is speciŜed to not be in Q. SaSW, Willem -- Disclaimer: I am in no way responsible for any of the statements made in the above text. For all I know I might be drugged or something.. No Iım not paranoid. You all think Iım paranoid, donıt you ! #EOT === Subject: Re: smallest disk covering a set of points > As a small exercise: Is there a smallest rational number that is not > smaller than sqrt(2) ? Given that this is cross posted to comp.programming - yes, if you are representing that number in a speciŜc datatype, there is a smallest number that is not smaller than sqrt(2): dave@feathers:~/progs/c> cat smallest_over_root2.c int main() { double value,increment; value=3; increment=1; while (increment) { if (value*value >= 2) { value-=increment; } else { value+=increment; increment/=2; } } printf(Smallest double over root(2)=%.80fn,value); } dave@feathers:~/progs/c> ./smallest_over_root2 Smallest double over root(2)= 1.41421356237309492343001693370752036571502685546875000000 Same answer if the test is (value*value > 2). So two questions that are long overdue, if they hasnıt already been answered, are: did the OP want a mathematical answer or a programmatic answer to the problem, and, if the latter, does he have mathematical software that can deal with surds or is he using bog-standard datatypes? Fascinating discussion though. One of the most interesting Iıve read for a long time. Dave. === Subject: Diagonal approximation of complex matrices by support1.mathforum.org (8.11.6/8.11.6/The Math Forum, $Revision: 1.9 primary) id i4PLeGk03366; Hello all, Given a square complex matrix, I am trying to Ŝnd the optimal diagonal approximation of the matrix. Precisely, if G is the given complex matrix and H is the set of all diagonal complex matrices, then I want to Ŝnd Hd in H such that Hbd = arg min sigma_max (G - Hbd) where sigma_max is the maximum singular value. When G is a 2x2 matrix, using Ŝrst and second order optimality conditions, I am able to show that the optimal diagonal approximation is simply the diagonal elements of G. However, when the dimensions of G are higher than 2x2, numerical evidence suggests that this simple result does not hold. I did some literature survey, but could Ŝnd any papers dealing with this problem. I came across some papers (e.g. http://db.cwi.nl/rapporten/abstract.php?abstractnr=890) where the spectral radius of (G - Hbd) is minimized, but the approach is only numerical. I would much appreciate, if someone can point me towards any papers where this problem has been discussed. Any helpful suggestions towards Ŝnding the optimal diagonal approximation (and parametrizing all solutions, if non-unique) will be extremely helpful. Vinay === Subject: Re: Differentiation by support1.mathforum.org (8.11.6/8.11.6/The Math Forum, $Revision: 1.9 primary) id i4PLl8v03873; >Give an example of a unifomrly continuous function on [0, 1] that is differentiable on (0, 1) but whose derivative is not bounded on (0, 1) i m not sure about this question, but how about f(x):= sqrt(X) on I:=[0, 1] it is unifomrlly continuous since I is close bounded interval, n f(x) is differentiable on (0,1) except x=0 by using the deŜnition of limit, fı(x) is not bounded on (0, 1) since the limit of fı(x) does not exists when x=0; === Subject: SMSU Problem Corner The new problems have been posted. Please visit us at http://math.smsu.edu/~les/POTW.html I am (Ŝnally) slogging through the backlog of old problems. === Subject: Re: Subset of Irrationals >Any help with this is greatly appreciated. Let u be a subset of (0,1) such >that (a) every member of u is irrational and (b) if s and t are any two >members of u, s-t is irrational. Let K be the set of all subsets of (0,1) >satisfying uıs requirements and L is a set listing the cardinality of the >sets in K. What is the largest cardinal in L? > DeŜne an equivalence relation on (0,1) by letting r~s if and only if > r-s is rational. > Clearly, r~r, if r~s then s~r, and if r~s and s~t, then since r-s and > s-t are rational, so is their sum, r-t, so r~t. Thus this is an > equivalence relation. > A subset of (0,1) will satisfy your conditions (a) and (b) if and only > if it intersects each equivalence class in at most one element, and > contains no elements in the equivalence class of 1/2 (the rationals). > I claim that each equivalence class is at most countable. For given an > equivalence class, and a Ŝxed representative r, then the set > { r - s: s in [r] } > is a subset of Q, and clearly in one-to-one correspondence with [r]. > Thus, there are 2^{aleph_0} equivalence classes. If you accept the > Axiom of Choice, there is a set that contains exactly one > representative from each class; remove the rational representative, > and obtain a set in K of cardinality 2^{aleph_0}. Since clearly no > largest cardinal can be in L, this is the answer. past two days Iıve been trying to prove that 2^Aleph_0 is the answer by direct construction. After some trial and error I discovered this approach. The largest cardinal in L will be at most 2^Aleph_0 since any subset of the irrationals can be no bigger than this. Map every irrational number in (0,1) to some subset of the irrationals near 1/10 in the following way. For the decimal expansion of any irrational in (0,1), let each digit correspond to its numerical value except zero, which corresponds to 10. Then, starting with 0.1, the number of zeros after the 1 corresponds to the factorial value of the Ŝrst digit. All subsequent digits are found by Ŝrst adding another 1 digit and then adding additional zeros; with the number of additional zeros equaling the factorial of the sum of the previous and current digit of the original number. For instance we can Ŝnd the new irrational that 0.1219... maps to by starting with 0.1. The Ŝrst digit in 0.1219... is 1 and 1!=1 so we add one zero to 0.1 and add another 1 digit to get 0.101. The second digit in 0.1219... is 2 and adding that to the Ŝrst digit, 1, gives 3 and 3!=6. So we add 6 zeros followed by another 1 digit to 0.101 to get 0.1010000001. The third digit in 0.1219... is 1 and adding it to the sum of its previous digits gives 1+2+1=4 and 4!=24. So we add 24 zeros to 0.1010000001 and add another 1 digit to get 0.10100000010000000000000000000000001. Continuing in this way we get: 0.1219... <----> 0.10100000010000000000000000000000001000... Another example: 0.2212... <----> 0.10010000000000000000000000001000000000... In fact, this technique should map every real in (0,1) to a unique irrational. So we have 2^Aleph_0 irrationals consisting of 1ıs separated by ever larger sequences of zeros and the difference between any two of these irrationals is another irrational. For instance we can subtract 0.2212...ıs counter part from 0.1219...ıs counter part to get: 0.00090000009999999999999999999000000999... This number is irrational. A rational number must have a repeating decimal sequence, like 00090999: 0.0009099900090999000909990009099900090999... And this cannot be added to something like: 0.1010010000001000000000000000000000000100... to get a number consisting of only 1ıs and 0ıs. So we have constructed a set of 2^Aleph_0 irrational numbers and the difference between any two of them is another irrational number. There must be sets in K with cardinality 2^Aleph_0 and, since this is the largest cardinal that could possibly be in L, this is the answer. RL === Subject: Re: Big Bertha Thing blogs Big Bertha Thing Chair Cosmic Ray Series Possible Real World System Constructs http://web.onetel.com/~tonylance/chair.html Access page JPG 18K Image Astrophysics net ring Access Site Newsgroup Reviews including uk.railway Detail from frontspiece painting showing, so called arms up to chair sedan. Caption;- A Chinese Street The World and Its People Asia With Special Reference to British Possessions Published by Thomas Nelson and Sons 1903 Without Author or Editor Name (C) Copyright Tony Lance 1998 Distribute complete and free of charge to comply. Big Bertha Thing Serpico Serpico was an honest cop in New York, that was all he ever wanted. As he lay, in his hospital bed, recovering from being shot in the face, all he could bear to watch on TV was Sesame Street. At one time or another, he had upset every cop on the force, except one. Now, he even had mayor John Lindsay, dancing in attendance. He still thought, it was worth it. Now he lives in Switzerland, on a disability pension. There is this incredible sense of deja vu, even down to the walking stick. Most days he feels Ŝne, even if occasionally he could sleep for a week. Bibliography;- Serpico by Peter Maas (C) Copyright 1973 by Peter Maas and Tsampa Company, Inc. Published by William Collins Sons & Co.Ltd. Glasgow. Serpico Ŝlm by Paramount Pictures True story covered by New York Times (3rd February 1971) Tony Lance mickalice@big-bertha-thing.com Big Bertha Thing handcart 1. Gardening section of Daily Telegraph, on Saturday 17th November 2001, shows full front page spread picture of pin-wheel rickshaw. 2. For another picture see;- http://web.onetel.com/~tonylance/pinwheel.html 3. Both show load perfectly distributed. 4. Both are idealized pictures of a rickshaw that does not exist. 5. A 19th century cheque-book journalist requested a picture of an unnusual rickshaw, which was promised for tomorrow. 6. A portrait painter, a landscape artist and a cartoonist submitted quotes, which the cartoonist won. 7. A wheelborrow uses straight arm technology. 8. In common with a handcart, the so called pin-wheel rickshaw, uses bent arm technology. 9. It is physically impossible and so unviable. 10. This is a scientiŜc cartoon, some work, some donıt. Tony Lance mickalice@big-bertha-thing.com === Subject: Matlab 6.5 I can send you 3 CDs containing Matlab 6.5 (free of charge) if you can provide ONE of these packages: 1) Mathcad 11. 2) Maple v.9.0 or v9.5. 3) Multisim 7 (circuit simulator). 4) Mathematica 5.0. No money involved in the exchange. Trucho === Subject: Re: Matlab 6.5 That would be the *legitimate* version of Matlab, correct? Trucho Nemesis schrieb im Newsbeitrag > I can send you 3 CDs containing Matlab 6.5 (free of charge) if you can > provide ONE of these packages: > 1) Mathcad 11. > 2) Maple v.9.0 or v9.5. > 3) Multisim 7 (circuit simulator). > 4) Mathematica 5.0. > No money involved in the exchange. > Trucho === Subject: 3rd D.P. Roots Is there any rule (or rule of thumb) for Ŝnding roots (real or complex) of polynomials with this form? f(x) = Ax^3 + Bx + C (A, B, C not 1 or 0) For example (or speciŜcally in this case, if there are different cases, even with the above restriction): f(x) = 2x^3 + x - 2 In advance, I thank you for your help, even if this question is simple. John === Subject: Re: 3rd D.P. Roots Googling solving cubic equation gives 69,000 hits, the Ŝrst one http://www.1728.com/cubic2.htm looks particularly simple. > Is there any rule (or rule of thumb) for Ŝnding roots (real or complex) of > polynomials with this form? > f(x) = Ax^3 + Bx + C > (A, B, C not 1 or 0) > For example (or speciŜcally in this case, if there are different cases, > even with the above restriction): > f(x) = 2x^3 + x - 2 > In advance, I thank you for your help, even if this question is simple. > John === Subject: simple limit laws boundary=----=_NextPart_000_0027_01C44254.9626AE60 ------------------------------------------------------------- -------- charset=utf-8 In one of my books, I have the following f Œ(x).89x = f(x + .89x) - f(x) By how did they get there (step by step) What I know is the following f Œ(x).89x = [lim(.89x->0) (f(x+.89x) - f(x))/.89x)] * .89x =...?.. = f(x + .89x) - f(x) (using of course the well-known limit laws) vielen dank fuerıs nachdenken === Subject: Re: simple limit laws > In one of my books, I have the following > f Œ(x).89x = f(x + .89x) - f(x) > By how did they get there (step by step) They didnıt. Itıs false for most f. > What I know is the following > f Œ(x).89x = [lim(.89x->0) (f(x+.89x) - f(x))/.89x)] * .89x > =...?.. > = f(x + .89x) - f(x) > (using of course the well-known limit laws) Thatıs false too. If delta x -> 0, both sides give 0 in the limit. === Subject: Re: simple limit laws X-NFilter: 1.2.0 > In one of my books, I have the following > f Œ(x)?x = f(x + ?x) - f(x) > By how did they get there (step by step) > What I know is the following > f Œ(x)?x = [lim(?x->0) (f(x+?x) - f(x))/?x)] * ?x > =...?.. > = f(x + ?x) - f(x) > (using of course the well-known limit laws) The deŜnition of differentiation is: fı(x) = [lim(dx --> 0) (f(x+dx) - f(x))/dx ] so it shouldnıt be too much of a stretch to see that fı(x)*dx = f(x+dx) - f(x) for inŜnitessimal dx.