mm-218 === Subject: Congruence Involving 6 & Some Sums-of-SumsLet, for each nonnegative integer k,a(6k) = a(6k +1) = 1;a(6k +2) = a(6k +5) = 0;a(6k +3) =a(6k +4) = -1.Let A(0,m) = a(m);and for all positive integers n, and for nonnegative integers m,A(n,m) = sum{k=0 to m} A(n-1,k);Then, for q and r = any nonnegative integers:m!*(A(q,m+1) -binomial(q+m,q-1))is congruent tom!*A(r,m) (-1)^m (mod {m+q+r}).So, more specifically, from the above we get:For ODD m,(m-1)!*A(r,m)is congruent to(r+m)!/(m r!) (mod {m+2r+1}).For EVEN m,(m-1)!*A(r,m)is congruent to(r+m-2)!/(m (r-2)!) (mod {m+2r-2}).(Someone might enjoy confirming the above congruences...)I wonder if any of these congruences have any interestingnumber-theory === (Goal:Coprime-Grid)For a positive integer n,arrange 1 through n^2 in a square grid like so:1 2 3 4....nn+1 n+2 n+3... 2n2n+1 ... 3n...n^2-n+1... n^2What is the minimum number of switches neededto get the n-by-n arrangement of the integers whereEVERY pair of adjacent integers is coprime?By adjacent, I meanimmediately next to in the directions of up, down, left, right.By switch, I meanthe exchanging of two adjacent integers' positions.So, we might have, for m=2,1 23 4We can switch the 3 and 4, so we then have1 24 3Since every adjacent pair is now coprime, only 1 switch is needed for n = 2.Yes, ts puzzle was inspired by Sam Loyd's 14-15 Puzzle.(Or was it the === calculus vs. discrete mathTs might just be echoing James's post, and another one too, butthere are a few slogans one comes across in learning maths. Two thatstuck in my mind were that the easier a problem is to state the harderit is to solve (above a certain level), and there are reasons thedefinitions are hard and the theorems easy. Perhaps it is tsobservation alluded to that in calculus there are many problems allhaving the same solution, yet in discrete maths it is often that eachhas a different method for solving it, if one even exists at all. Apersonal favourite would be the if there are six people at a partythere are 3 mutual friends or 3 people who don't know each other, easyproof, generalize it and it becomes imposssibly difficult to solve.Perhaps Erdos's observation (of another problem) that maths isn'tready for these tngs yet is === see me then in the industrial-punk outfits I used to wear inmy: > more angst-filled youth.:: No problem with that. I have worn a gilette blade hanging from a: safety pin stuck through the flesh of my shoulder myself. You: obviously did not understand the reference. Don't go telling what Eco: would be proud of if you don't have a founded command of s works.: That was from Focault's Pendulum, the umbanda ceremony takes place at: the end of Casaubon's binge in Brazil. Read it if you care, it's a: very spooky book about knowledge.I _have_ read Foucault's Pendulum. It _was_ a very powerful book on thenature of knowledge. Don't go around pretending like everyone is moreignorant than you. It is quite a disgusting display.I would love to discuss Eco in depth with you, but you need to correct yourtone before that happens, and I would prefer to take that somewhere moreappropriate.(By the way, I'm sure you have seen, my dear Jorge de Burgos, that there isa strange similarity of the heresy of Aristotle's work on humor and levityand the heresy I am accused of by yourself and others, of being arrogantenough to enjoy my work and my creativity. I know, I know... I should bemore solemn when walking through the halls of knowledge you wish tocontrol...)[...]: Look Galathaea, you've been asked by many others in nicer and ruder: ways, what it is that you are talking about. Posting a long list of: references will only convince people that you are out to show off how: well read you are. Why don't you state one single mind bogling fact in: the lines of there is an isomorpc relationsp between the set of: regular verbs of the natural language Q, and the set of all halting: programs that can be encoded by a string of length N over an alphabet: Z and ts is due to an underlying heyting structure. Even sometng: weaker will do. Even answering my little stupid question will do.: Remember, nobody asked you questions in the first place. It was you: who came and said hey everybody look at my bright idea! and then: simply failed to produce it. As I told your buddy Mitchy, until now: you've been all width and no depdth. Now show some meat. (no pun: intended ;p)I posted a central question that was the focus of my towards a constructiveeducation thread. In fact, it's right there in the title. Should weexpand the education of logic? Restructure a bit, maybe move certain tngsto younger ages? Include the nonclassical?In particular, I felt it would be less controversial to focus on addingHeyting structures to the curricula. There are tons of communities usingthem implicitly or explicitly in their work. I made the assumption thatsome of these people are lying dormant out there, aware of the work in thefields but not really bringing them up as topics very often. I've seenmentions every now and then on sci.math of some of the topics, mitch hasbeen fighting away on sci.logic over similar issues, and since I knew ofwork in a lot of other fields about it, I thought I would try to see ifthere was any sort of minority community I could summon to discuss thattopic.I wasn't trying to sell anytng grand or pass off some gobbledygook in someattempt to deceive. I was asking questions and sharing ideas.In other words, I made the opposite assumption than you, arrogant Guenther,that the people communicating on these groups might possess some knowledgeof what I was talking about and have opinions to share.My entire point has already been stated quite a number of times, that themodels we are constructing about the world around us, the languages we usein natural languages, folk-science, and even quite a lot of modern science,all make heavy use of nonclassical logics. There is still quite a traditionto use classical logic as the metamodel, wch then faces difficulties withclassification of what types of statements it can really be applied to. Itis not universally applicable to all statements, and the study of ts isfairly well established.So I also introduced my suspicion as to why classical logic gets presentedin the ways I have seen it presented, as the universal logic of everytng.I suspect that people really want tngs to be true or false always,either-or, that they desire at least metaphysically for such aclassification to exist even when we have known at least for three quartersof a century that we cannot always deduce such from our math. Ts Iassociate with monotheism's popularity, and I am not the only one as I pointto the quote by R. M. in s book on semiotics makes the same claimand attributes its origin to Wtehead.And I believe that if people understood the way we can formalise differentstructures of reasoning about the world, how we can build various models andtest them to our experience, and along the way were shown that alot of ourmost useful models today are built in structures of nonclassical logics,maybe some of the fundamentalism I see in the world would fade. Just alittle. I'm don't expect major changes.Its just that I tnk there is sometng inherently unhealthy about aframework or world view that forces people to attribute an absolute truth orfalseness to all statements in their mind. It makes people build defensivepsychologies to hold on to whatever world-view they have constructed whenlogical consistency starts kicking in, and other ideas become excluded tothe point where hatreds are formed.If you don't believe me, just look at the response these threads havegotten, from yourself included. None of what I mentioned was factuallyincorrect to my knowledge (or, at least, no one has been kind enough topoint to any errors, though I'd expect one or two errors lying aroundsomewhere), and indeed it was topical to all groups. However, it wasn't thetype of post some people wanted. My posts have been playful, they haven'tneeded any rigor because the papers I referred to included all of that. Iwas just asking a simple question, wch I've asked several times now. Andalthough I've asked it several times, there is still an anger from those,like yourself Guenther, who admit they don't know what my question has been.There have been positive responses too. Obviously mitch who has facedsimilar negativity over on sci.logic, has contributed alot. Some peopleasked questions in a very friendly manner, and I was immediately friendlyis overdue unfrotunately) for those who were open enough to allow me toexplore more of the ideas because they are curious.I like open, curious people who don't desire to post contentless negativitywhen sometng doesn't fit inside their worldview, because that is aprerequisite of true science. I believe that there is a certain mentaldynamic that quests for certainty. Some choose religion, particularlymonotheism, because it often screams out quite loudly its importance as thesource of the certain absolute truth and adds some nice, though unseen,perks through Pascal's wager. Others choose science, wch at first seemsto offer a more secure form of certain absolute truth in observablecorrelation.I myself love science. It is the one-stop source of models to predictreality with. But there is still uncertainty there. The study of modelshas shown that there are numerous ontologies with identical observablepredictions. There are even huge numbers of models out there that dopredict different observations but only through experiments we do not yethave the capability (or energies) to explore yet. Science is not a sourceof certainty. It is a playground of competing models. And I believe thatunderstanding better what models are, how they carry a logical structure,and how they get tested to observation could stop a lot of the rudeness onthe playground.Take, for instance, superstring theory. As with all ideas when they arefirst introduced, it has been attacked quite a lot from many differentdirections. With more research in the field, it has been able to establiself as a topic legitimate to study in physics curricula, even enteringundergraduate courses these days. So what was the content of the attacks?Excluding mathematical corrections to various papers (wch I do notconsider attacks but legitimate scrutiny of method), the biggest attackshave been on the freedom of predictability in the theory. Unique orotherwise natural solutions are still not well established. There is stilltoo much freedom in the theory. Other attacks (though less frequent) arebothered by the large dimensionalities or see certain preferred frames inthe theories as problems despite the lack of observability. There has beenalong the way a certain meanness in some of the attacks, a belittling.I have my suspicions that some of the anger response is residualmanifestations of the male alpha problem. In past societies, erarces ofpower formed through displays of strength and aggressiveness. It was usefulbecause strength and aggressiveness were useful on a biological level.Nowadays, I see the same quest for erarces in science, in particular thesame quest for absolute truth centered on one model. That is why, forexample, there is a standard view of quantum mechanics and alternateinterpretations are so commonly demeaned.So you see, Guenther, I have now expressed yet again the whole point of anyof ts. Along the way, you will notice that I have had to fight my shareof alpha attacks. But I have always asserted, as I do to you now, that Ihave a right to ask the questions I have, in the forums I have, at the timeI have === binomial and sum> The following formula,> i i> C C > n 1 n n+1> SUM ----- -- = 2, with n integer> i=1 2i-1 2i> C> 2n> i n!> where C = ---------,> n i! (n-i)! can be easily found using two formulas related to Catalan numbers {C_n} :> (2n)!> C = ---------, for all n>0, and C = 1 ;> n n! (n+1)! 0> n> SUM C C = C .> i=1 i-1 n-i n>A elementary proof, using binomial coefficients properties for example, would be nicer.>TigertibA start?...Your sum is 2 for n = 1.So if we take the differences between the sum at n+1 and the sum at n,we should always get 0 for each n >= 1.So,(n!(n+1)!/(2n)!)sum{i=1 to n} (i2)!(n2-12)!/(i!^2 (n+1-i)!(n-i)!(2i-1))should equal, for all n >= 1,((n+1)!(n+2)!/(2n+2)!)*sum{i=1 to n+1} === rearrangement question....hot-girl> .........> i know that if sigma An is absolutely convergent,> then any rearrangement is also absolutely convergent,> and furthermore all rearrangement of ts series have the same sum.> i saw the next infinite series> sigma 1/{(2k-1)(2k+1)} = 1/(1*3) + 1/(3*5) + 1/(5*7) + ...> thus> sigma (1/2)[{1/(2k-1)}-{1/(2k+1)}]> = (1/2)(1/1 - 1/3) + (1/2)(1/3-1/5) +.........> = 1/2True. It is easy to prove that the partial sumsof sigma 1/{(2k-1)(2k+1)} are k/(2k+1)and these have limit 1/2.> ...> sigma {k/(2k-1)} - {(k+1)/(2k+1)}> = (1 - 2/3) + (2/3 - 3/5) +............> = 1but the series whose summands are((-1)^k) k/(2k-1)is not absolutely convergent.If a series of real numbers converges, but not absolutely,its terms can be rearranged to produce === RecursionsWell-known, I am sure...For a fixed positive integer n,Wch conditions on the fixed coefficients {c(k)} and on the initial a's,a(k) for 0<=k<=n, are necessary and sufficient for the sequence{a(k)} to be periodic, wherea(m) = sum{j=1 to n} c(j)*a(m-j) ?For example:a(m) = sum{k=1 to n} a(m-k)(-1)^(k+1)is always periodic,with period2n+2 if n is === transcendentals> Obviously, a number is of the form Nc + r for rational r and integral> N iff its ! representation is eventually constant.Looks right.I am still working on the only if part.> It would be interesting if PI has a repeating base ! representation.Ts would be easy to computeAnyone out there with a large number program and a lot of spare computertime?Pseudo-code:' r = a real numberinput r' ignore integer partr = Fractional(r)' calculate coefficientsn=2do ' coef=coefficient coef = integer( n! * r ) print n, coef r = r === transcendentals> Russell Easterly [NonBreakingSpace].8b.96.87.8c .97.99.95 .93fi.92.9b.93.87The factorial base allows you to create a lot of transcendentals from e.> [snip examples]> I spent a couple of minutes tnking about base ! and although I have not> read the relevant older threads in sci.math, it appears that ts base is> particularly _bad_ in terms of representations.I gave a very short description.It may be you didn't understand the system.Integers:Each position, n, represents n!.The allowed coefficients are 0-n.Every integer has an unique representation:! - base 100 - 01 - 110 - 211 - 320 - 421 - 5100 - 6...> For example: 1/2 = Sum(1/[n*(n-1)], n=2..+oo) = Sum((n-2)!/n!, n=2..+oo) => 0.01126... (base !) and> 1/4 = Sum(1/[n*(n-1)*(n-2)], n=3..+oo) = Sum((n-3)!/n!, n=3..+oo) => 0.001126... (base !)Fractions:Each position represents 1/n! (n>1).Coefficients can be 0 through (n-1).Like fixed radix bases, the representation for certain numbers is notunique.(e.g. in base 10, 1.0 = 0.999...)All rational numbers have two representations: one finite and one infinite:1/2 = 1/2! = .1 = .023456...1/4 = 1/3! + 2/4! = .012 = .011456789...1/11 = 2/4! + 5/6! + 3/7! + 1/8! + 4/9! + 10/11! = .002053140A= .0020531409BCDE...Russell- 2 many 2 === trying to make sense of sometng that was mentioned in a book I'mlearning topology from.a) First he states that defining the product topology of spaces (X,Tx) =(Y,Ty) = R by Bxy = {O1 x O2 | O1 in Tx, O2 in Ty} will not work sincealthough the sets (0,1) x (0,1), and (2,3) x (2,3) are in Bxy,[(0,1) x (0,1)] U [(2,3) x (2,3)] is not.Ts made sense to me. Later he mentions that a workable way to generate atopology T is to define it as the topology having Bxy as a basis. Ok tsmakes sense.But he says the following just before ts wch confused me:If it were [an open set] (referring to [(0,1) x (0,1)] U [(2,3) x (2,3)]froma) ), then <0.5,2.5> in (0,1)x(2,3), but <0.5,2.5> is not in[(0,1)x(0,1)] U [(2,3)x(2,3)]. Thus T is not closed under unions and so isnot a topology.Comments:First of all, even if we use the basis Bxy to generate a topology T thenagain, <0.5,2.5> in A = (0,1)x(2,3), but <0.5,2.5> is not in B =[(0,1)x(0,1)] U [(2,3)x(2,3)]. A and B are both open in T and the topologyis obviously closed under union.Second, in what way can [(0,1)x(0,1)] U [(2,3)x(2,3)] be thought of as a'union' of (0,1)x(2,3) and any open sets (reffering to the statement Thus Tis not closed under unions)?Does ts guy simply not know what he's talking about or am I missingsometng very obvious or have made some basic logical error?l8r, Mike N. === ts problem but have no idea how to tackle it.2 rigid rods of unit length are nged to each other. Initially they areparallel to each other, much like a closed pair of divider.Ts divider is placed on a piece of paper. What is the minimum area of thepaper wch allow the divider to be opened such that the angle between thetwo legs extend from 0 to 360 degrees. The divider is to touch the paperand no part of the divider is to extend beyond the paper throughout thewhole process.What area === area to flip 2 nged rodsthe area of the smaller unnged end of the two rods (area-wise) plusthe larger unnged end's area, plus a fudge factor (I'm supplying nomath because you didn't specify the shape of the paper). You didn'tspecify that the rods were laying on the paper.>I thought of ts problem but have no idea how to tackle it.>2 rigid rods of unit length are nged to each other. Initially they are> parallel to each other, much like a closed pair of divider.>Ts divider is placed on a piece of paper. What is the minimum area of the> paper wch allow the divider to be opened such that the angle between the> two legs extend from 0 to 360 degrees. The divider is to touch the paper> and no part of the divider is to extend beyond the paper throughout the> whole process.>What area of === to flip 2 nged rods>I thought of ts problem but have no idea how to tackle it.>2 rigid rods of unit length are nged to each other. Initially they are> parallel to each other, much like a closed pair of divider.>Ts divider is placed on a piece of paper. What is the minimum area of> the paper wch allow the divider to be opened such that the angle between> the> two legs extend from 0 to 360 degrees. The divider is to touch the paper> and no part of the divider is to extend beyond the paper throughout the> whole process.Since no part of the divider is to extend beyond the paper, we assume that it is laid down on the paper, not stood up on one point. We further assume that the whole of (the underside of) the divider must be in contact with the paper throughout any rotation operation, and that the paper does not move.With these fairly simple assumptions in place, it's hard to see how the answer will be anytng other than pi square units (area of a circle of radius one unit).> What area of mathematics deal with such problem ?Geometry.-- Richard Heathfield : binary@eton.powernet.co.ukUsenet is a strange place. - Dennis M Ritce, 29 July 1999.C FAQ: http://www.eskimo.com/~scs/C-faq/top.htmlK&R answers, C books, === to flip 2 nged rods> I thought of ts problem but have no idea how to tackle it.> 2 rigid rods of unit length are nged to each other. Initially they are> parallel to each other, much like a closed pair of divider.> Ts divider is placed on a piece of paper. What is the minimum area ofthe> paper wch allow the divider to be opened such that the angle between the> two legs extend from 0 to 360 degrees. The divider is to touch the paper> and no part of the divider is to extend beyond the paper throughout the> whole process.> What area of mathematics deal with such problem ?A circle eith radius equal to the length of one rod (or the longer rod, ifthey are not the same)? Unless I've understood it incorrectly, it's prettysimple. One rod lies on a radius of the circle, with the nge at thecenter. Then the other rod is swung out around and sweeps over the entirearea of the circle before it gets to 360 degrees, at wch point it is backwhere it started.But... maybe I === flip 2 nged rods I thought of ts problem but have no idea how to tackle it. 2 rigid rods of unit length are nged to each other. Initially they are> parallel to each other, much like a closed pair of divider. Ts divider is placed on a piece of paper. What is the minimum area of> the> paper wch allow the divider to be opened such that the angle between the> two legs extend from 0 to 360 degrees. The divider is to touch the paper> and no part of the divider is to extend beyond the paper throughout the> whole process. What area of mathematics deal with such problem ?>A circle eith radius equal to the length of one rod (or the longer rod, if> they are not the same)? Unless I've understood it incorrectly, it's pretty> simple. One rod lies on a radius of the circle, with the nge at the> center. Then the other rod is swung out around and sweeps over the entire> area of the circle before it gets to 360 degrees, at wch point it is back> where it started.>But... maybe I did understand it wrong.>Jonathan> It can certainly be done in a circle of that radius, but it can also be done in a half circle of the same radius if the nge is allowed to change positions,If r is the length of each segment, it can be done witn the curve|x|^s + |y|^s = r^s, for s = 1, where the circle would be s = 2.I tnk it can be done with s = 1/2.It may well be that the minimal s for wch it can be done gives the desired minimal enclosed area curve.On the other hand, there are closed curves enclosing arbitrarily small areas in wch a line === Re: Do Prime Algebraic Numbers even exist? > Computational complexity not only involves the number of operations, but > also the complexity of operations. Operations on large numbers are more > complex than operations on small numbers. When you look at it from a pure > mathematical viewpoint it is a bit different. But when you are actually > implementing stuff the largeness of numbers gets to play a big role. Well, here's the whole computation. Complexity is in the eye of the > beholder, but ts doesn't look too complex to me. Formulas for the > iterations are below. Use fixed-width font to view.Well, I have said that I did not want to use a bignum package, and indeed,the first line that goes wrong because I do not use such a package is notedbelow: > 18 17 5 7 11752497748 581123613 18 17 5 7 -1132404140 581123613The second line is what I get (going to unsigned long does not help either).Going to double precision will give me some space, but not much. So toget the proper value I need a bignum package wch adds === complex integration questionsI have a few quick questions about integration of complex functions.first, how does one integrate over a curve that crosses a branch cut?is it possible? if c(t)=2e^it, t in [-pi,pi], then can integration of1/(z^2-1)=1/2(1/(z-1)+1/(z+1)) be done as usual? what care do i haveto take when doing ts?and lastly, is integration of complex functions ever done over regionsin the plane instead === (model-free common sense steering): Neural networks are model-free estimators, in that they do not requirean: in-depth understanding of the phenomena they are modeling.:: http://www.arcon.com/arconneu.html:: THE MATHEMATICS OF CROSSING THE STREET:: You are at the curb deciding, Should I: cross the street? Well, it depends.:: AT THE CURB: The walk light is on, but you see a: truck approacng fast. How fast?:: There is no exact number. Instead, there are an infinite number of: possibilities - from 1kph to over 100kph and everytng in between. You: don't have a radar gun, so instead you watch the truck for a second ortwo,: and sum its speed up in two words very fast. That is good enough.Phew.: Your senses have told you the truck is coming very fast, but you need more: information before you can decide whether or not to risk crossing. Howfar: down the street is the truck? Is it slowing down? Again, there are no: exact numbers, so you sum up the situation - close, not slowing quickly: enough.:: Somehow your brain adds fast + close + not slowing quickly enough,and: warns you instantly that the risk is gh. It is purely cognitiveprocess.: It involves a complex combination of sensory information and experience.:: ...Since there are no exact numbers in ts story, the mathematicalversion: must be told with fuzzy numbers...:: But, the process is still not quite over. Should I wait or cross? Youhave: to make the decision. Risk tolerance leads to different spins and endings.: If you walk with a cane, you reason, The risk is gh, so I'll wait. You: watch as the truck runs the red light. If you are a jogger, impatient to: cross, you disregard the evidence, step into the intersection, and jumpback: just in time to save your life.$#!! Where was my head? =): http://www.decyde.com/crossingthestreet.html:: Fuzzy logic works the way that humans tnk as opposed to the way that: computers typically work. For example, consider the task of driving a car.:: You notice that the stoplight ahead is: red and the car ahead is braking. Your: mind might go through the thought process,:: I see that I need to stop. The roads are: wet because it's raining and there is a: car only a short distance in front of me.:: Therefore I need to apply a significant: pressure on the brake pedal.:: Ts is all subconscious (in general), but that's the way we tnk - in: fuzzy terms. Do our brains compute the precise distance to the car aheadof: us and the exact coefficient of friction between our tires and the road,and: then use a Kalman filter to derive the optimal pressure wch should be: applied to the brakes? Of course not. We use common-sense rules and they: seem to work pretty well. On the other hand, when we do finally get around: to pressing the brake pedal there is some exact force that we apply, say: 1.326 pounds. So although we tnk in fuzzy, noncrisp ways, our final: actions are crisp. The process of translating the results of fuzzyreasoning: to a crisp, nonfuzzy action is called defuzzification.:: http://www.innovatia.com/software/papers/fuzzy.htm:: ...In particularly vast networks in fast moving environments, the split: second it takes to traverse the circuit is greater than the time it takes: for the situation to change. In reaction, the last node tends tocompensate: by ordering a large correction. But ts also is delayed by the longjourney: across many nodes, so that it arrives missing its moving mark, birtngyet: another gratuitous correction.:: The same effect causes student drivers: to zigzag down the road, as each late: large correction of the steering wheel: overreacts to the last late overcorrection.:: Until the student driver learns to tighten: the feedback loop to smaller, quicker: corrections, he cannot help but swerve down: the ghway hunting (in vain) for the center.:: Ts then is the bane of the simple auto-circuit. It is liable toflutter: or chatter, that is, to nervously oscillate from one overreaction to: another, hunting for its rest. There are a thousand tricks to defeat ts: tendency of overcompensation, one trick each for the thousand advance: circuits that have been invented.:: http://www.kk.org/outofcontrol/ch7-c.html:: Fuzzy systems are based on: storage of common-sense rules.:: For example, a fuzzy Army-ant robot controller might have the fuzzy: association if load is heavy, then signal for help longer. Fuzzyphenomena: admit degrees: some loads are heavier than others; some signal durationsare: longer then others.:: A single association (heavy,longer): encodes all combinations...:: Fuzzy systems reason with: parallel associative inference.:: A fuzzy system reasons with multivalued sets, instead of true or false: propositions, and it may adaptively modify its fuzzy associations from: representative numerical samples.:: http://www-2.cs.cmu.edu/~unsal/thesis/thesisch2.html:: Wired: What is fuzzy logic and why do critics call it the cocaine of: science?:: Kosko: Fuzzy logic is Spock's worst nightmare - a way of doing science: without math. It's a new branch of macne intelligence that tries to make: computers tnk the way people tnk and not the other way around. Youdon't: write equations for how to wash clothes. Instead you load a cp withvague: rules like if the wash water is dirty, add more soap, and if verydirty,: add a lot more. All wash water is dirty and not dirty - to some degree.: It's just common sense. But it breaks the old either/or logic ofAristotle.: That offends some scientists, who would like us to tnk and talk like: off/on switches. But they still haven't produced a statement of fact like: the sky is blue or E=mc^2 that is 100 percent true or 100 percentfalse.: Fact ain't math. You can never get the science right to more than a few: decimal places. That's one reason we find chaos when we look at tngs up: close...:: ...Fuzzy systems are universal computers. I proved that as a theorem - the: fuzzy approximation theorem. In theory, you can replace every book on: physics or economics with equivalent books that have fuzzy systems wherethe: equations used to be. Fuzzy systems are model-free estimators. You don't: have to guess at equations to build a bridge from inputs to outputs. Fuzzy: rules build that bridge for you. There is math bend the rules, but you: don't need to know it to program a fuzzy system. You can program it in: English. If the air is cool, turn the AC down a little. But the math is: not fuzzy. That's why you can capture fuzzy logic in a digital cp.:: Most of the first fuzzy systems were in control - as in adjusting a camera: lens or backing up a trailer truck to a loading dock. Now we're applying: fuzzy systems to wireless communications and multimedia. The fuzzy rulescan: randomly spread signals over a wide bandwidth or teach an intelligent: agent the kind of houses or sunsets you prefer. The math says we can apply: them anywhere. In practice, it may not be so easy.:: http://www.wired.com/wired/arcve/3.02/kosko_pr.html:: Fuzzy logic is a superset of conventional(Boolean) logic that has been: extended to handle the concept of partial truth- truth values between: completely true and completely false. As its name suggests, it is the: logic underlying modes of reasoning wch are approximate rather thanexact.:: The importance of fuzzy logic derives: from the fact that most modes of human: reasoning and especially common_sense: reasoning are approximate in nature.:: Boolean vs. Fuzzy: 300 years B.C., the Greek plosopher, Aristotle cameup: with binary logic(0,1), wch is now the principle foundation of: Mathematics. It came down to one law: A or not-A, either ts or not ts.: For example, a typical rose is either red or not red. It cannot be red and: not red. Every statement or sentence is true or false or has the truthvalue: 1 or 0. Ts is Aristotle's law of bivalence and was plosopcallycorrect: for over two thousand years.:: Two centuries before Aristotle, Buddha, had the belief wch contradicted: the black-and-wte world of worlds, wch went beyond the bivalent cocoon: and see the world as it is, filled with contradictions, with tngs andnot: tngs. He stated that a rose, could be to a certain degree completelyred,: but at the same time could also be at a certain degree not red. Meaningthat: it can be red and not red at the same time.:: Conventional(Boolean) logic states that a glass can be full or not full of: water. However, suppose one were to fill the glass only halfway. Then the: glass can be half-full and half-not-full. Clearly, ts disprove's: Aristotle's law of bivalence. Ts concept of certain degree ormultivalence: is the fundamental concept wch propelled Zader Lofti of UniversityBerkely: in the 1960's to introduce fuzzy logic. The essential characteristics of: fuzzy logic founded by m are as follows.::: In 1965, Lofti Zadeh formally developed multivalued set theory, and: introduced the term fuzzy into the technical literature. Nowadays, the: recent emergence of fuzzy commercial products, as well as new theory, has: generated a new interest in multivalued systems. Yet already engineershave: successfully applied fuzzy systems in many commercial areas : intelligent: subways automation, emergency breakers, cement mixers, Kanji characters: recognition, control air conditioners, automatic wasng macnes, guideof: robot-arm manipulators, and so on.:: Fuzzy systems store banks of fuzzy associations or common-sense rulessuch: as IF traffic is heavy in ts direction, THEN keep the light greenlonger: that might be articulated by an human expert. Some traffic configurationare: heavier that others and some green-light duration are longer than others,so: that, the single fuzzy association (HEAVY, LONGER) encodes all these: combinations. That is to say, fuzzy systems directly encode structured: knowledge but in a numerical framework : by entering the fuzzy association: (HEAVY, LONGER) as a single entry in a rule database we are defining an: input-output transformation.:: http://www.etse.urv.es/~aoller/fuzzy/fuzzy_logic.htm:: Fuzzy Logic is a computational paradigm capable of modelling the own: uncertainness of human beings. Fuzzy reasoning is notng else than aFuzzy: Logic-based formalism for encoding human knowledge or common sense in a: numerical framework. Indeed, the mathematical concepts on wch FuzzyLogic: is supported are very easy to understand. In a Fuzzy Controller, human: experience is codified by means of linguistic if-then rules, wch compute: control actions upon given conditions. Fuzzy Logic has been applied to: problems that are difficult to solve mathematically. One of its main: advantages lies in the fact that it offers a straightforward methodologyfor: modelling and controlling non-linear systems, wch are difficult to faceby: means of conventional techniques.:: http://www.wkap.nl/prod/b/1-4020-7359-3:: Fuzzy logic models itself on the pattern of human reasoning in its use of: approximate information and uncertainty to generate decisions. It was: designed (during late 1980s and early 1990s) to mathematically represent: vagueness and develop tools for dealing with imprecision inherent inseveral: problems. Normally, in digital computers one uses the binary logic where: the digital signal has two discrete levels : low (logic zero) or gh(logic: one); notng in-between. Fuzzy systems use soft linguistic variables(e.g.: hot, tall, slow, light, heavy, dry, small, positive, ...etc.) and a rangeof: their weightage (or truth) values, called membersp functions, in the: interval (0, 1), enabling the new computers to make human-like decisions.: Since human beings tend to use words rather than numbers to describe: behaviour patterns, fuzzy controls avoid the conventional rigidity of: computers and allow them to use parameters based on common sense.:: http://www.tribuneindia.com/2002/20021024/science.htm::: Fuzzy logic best summed up by common sense:: Computer Corner: Boyd:: Fuzzy logic was introduced to the world 27 years ago by Professor: Lotfi Zadeh in s Fuzzy Sets paper published in Information: Control magazine, though it is only recently that we've seen it: applied across a broad range of products.:: Some readers have asked for more explanation on fuzzy logic, so: here's an attempt to defuzzify the subject a little further.:: Simply put, fuzzy logic is aimed at enhancing our prissy computer: technology with a touch of common sense.:: One problem with the conventional digital computer is that it is: such a scrupulously either-or beast. It cannot be easily coaxed: to handle approximations or vague notions like young, a lot and: probably.:: Yet most of us rely on such terms daily because we happen to be: humans dealing with other humans, not robots building cars.:: It's an easy matter to arbitrarily program a computer so it: designates everyone falling into the age-range 0f 15 to 18: as being a youth. Such a precise category has come to be called: a crisp set since the emergence of fuzzy logic.:: Yet we all know some 14-year-olds can look older than some: late-developers turning 20. Such exceptions, however, cannot: be accounted for in conventional computing. Or at least not: without an inordinate amount of additional programming and: expense.:: As Tetsuya Yamada, a senior engineer at tac Ltd., replied: when I asked m if we couldn't just continue using conventional: programming and technology for controlling new products, instead: of fuzzy, Well, we could. And you could probably swim across the: Pacific if you got enough support from enough people. But ...:: To overcome ts problem, Zadeh was inspired to develop s fuzzy: theory and the math to go with it that could be used to create: fuzzy sets based on imprecise natural language.:: Each member in a fuzzy set (such as the youths and others considered: in the above example) is assigned one of a continuous range of values: (called the membersp value) between zero and one.:: Whereas in the above crisp set a 13-year-old going on 14 would still: have to be considered a minor and thus be designated as zero in: binary logic, fuzzy logic could assign m a membersp value of: say 0.1. Likewise, an immature 20-year-old who would normally fall: outside our either-or crisp-set range could be assigned a membersp: value of 0.9 depending upon the criteria we use to measure youth.:: Working out just what criteria to use, what values should be assigned: each member and deciding what rules are necessary to govern the: relationsps between members is the key to successfully applying: fuzzy control in products.:: In some applications, determining the optimum rules has become so: complex, some manufacturers have resorted to employing the aid of: neural networks, wch may be stretcng a good tng too far, given: fuzzy logic's original purpose to get round complexity.:: Still, the flexibility in herent in fuzzy is clearly useful in: dealing with approximate calculations, such as about 100.:: It can be used in artificial intelligence to provide us with an: almost true answer. It can also infer a common-sense result even: when the data is not precise.:: Our handwritten 5 in 250 would be treated as 5, not the letter S,: for instance, in Sony's fuzzy-based Palmtop computer.:: Wle we have all seen fuzzy logic-based products from the likes of: Matsusta, Sanyo and tac, one unlikely company that has made: fuzzy technology a central part of its business strategy is Omron: Corp.:: It began its research into fuzzy logic in 1984 and has since applied: for over 700 patents. Ts puts it in the forefront of fuzzy: applications in areas like factory and industry control, as well as: in medical equipment.:: In 1989, Omron also signed on lotfi Zadeh as a senior advisor.:: Earlier ts year at the Business Show in Harumi, Omron demonstrated: its fuzzy workstation. Omron manufactures both standard Motorola: 68040-based and 88000 reduced-instruction or RISC-based workstations: that can be fitted with a fuzzy inference board, turning them into: the world's first fuzzy workstations.:: Omron claims such a RISC-based workstation can aceve 4 billion: operations per second, an incredible speed if they haven't fuzzed: on the number. Fuzzy logic is used in the workstations to store: and retrieve fuzzy information and make inferences.:: Ranging in price from Y2.5 million to almost Y4 million (a US dollar: is about 120 Yens -FM), these macnes are not the kind of products: you will find down in Akihabara. (a section of Tokyo famous for its: quantity and variety of electronic goods -FM) Rather, they are: typically aimed at value-added resellers in niche markets, and: engineers who want to develop fuzzy applications, fuzzy databases: and expert systems, as well as fuzzy inference systems.:: However, the entrepreneurs among you may be interested in Omron's: FB-30AT fuzzy inference board for the IBM PC and compatible wares.: It features a 24 MHz FP-3000 fuzzy cp capable of processing up: to 128 rules, with five antecedents and 2 consequents. Training: software and a compiler is also available.:: Omron has also produced a fine little booklet on fuzzy called: Clearly Fuzzy that I dipped into when writing ts column.:: Tadas Katsuno, at Omron's public relations section, tells me: he still has a limited number of copies left that he will send: to the first readers of Computer Corner who write to m with: contact information.:: The address is Omron Corp., International Public Relations Section,: Omron Tokyo Bld., 3-4-10 Toranomon, Minato Ward, Tokyo 105.: --------:: - Farzin Mokhtarian: farzin@apollo3.ntt.jp::http://www-cgi.cs.cmu.edu/afs/cs/ project/ai-repository/ai/areas/fuzzy/doc/intro/j_times.tgz:: http://www.ece.utep.edu/research/webfuzzy/about.html:http:// www.sztaki.hu/~viharos/homepage/Publications/1999_ICIMS_NOE_ ASI99/ASI'99_ViharosMonostori.htm: http://www.bjarne.ca/pmflp.pdf: http://www.etse.urv.es/~aoller/fuzzy/fuzzy_logic.htm: http://www-pablo.cs.uiuc.edu/Project/PPFS/PPFSII/ FuzzyLogicControl.htmSometimes I really believe that people give many names to the same tngwhen it is sometng we really appreciate. There is model in there, but itis prior to numbers. It is topological, connective. It looks like:a -> band introduces a fundamental asymmetry we can play with.Automata build up digraphs of these upon wch they evolve through statetransitions. Abstraction neural nets are often lattices, though you toss ina loop or ring or whatever (like in nematodes) and you have recurrence.All of them say the same tng: you are passing information through astructure of transformations.I took a class in Control Theory once in my undergrad years, and theprofessor used to often suggest books to me by Norbert Wiener and others inthe cybernetics community or Bucky's synergetics. When I could understanddynamics better, I was able to get into Rene Thom and catastrophes throughanother suggestion when he was teacng a non-linear diffy-que class.The discrete becomes continuous.And the logics, all of them, so very useful. The dynamics they === Simple idea, mathematics and common-sense>You're really sounding like an idiot. If you want to say> mathematicians are all wrong you need to come up with> sometng they actually say === under quadratic constraintDaer all:I have a question about optimization.The description is as below:max. (x-t)'R(x-t)S.T. (x-m)'W(x-m)=ct, m, R, W, c is givent m x is a n*1 vectorR W is sym. matrixc is a scalarany body can solve ts === optimiziation.The description are as below:max. (x-t)'R(x-t)S.T. (x-m)'W(x-m)=ct, m, R, W, c is givent m x is a n*1 vectorR W is sym. matrixc is a scalaranybody can solve === majors?>I'm a gh school senior planning on studying pure math as a major> ts fall in college. What I'm wondering is, what kind of advice> could those of you who have already been through the experience offer> to people in my position? What kind of background is necessary (or> recommended) to begin college mathematics courses, and what could a> future math major do in order to get a head start? Are there any> books or other information sources that would be helpful? Any advice> is greatly appreciated.>If you haven't already, get some of the easier topics out of the way by> studying on your own: linear algebra, probability, number theory, set> theory, as much calculus as you can stand. If you don't find these topics> easy, change to accounting.On the contrary, if you find these topics easy, you are undoubtedly> taking a very superficial view of them. Math is not easy, and the myth> that it is, is one of the big tngs a gh-schooler needs to dispell> when s/he goes to college. Math has certainly never been easy for me, in part because I used tolearn it by rote like all too many people do. Mathematical *tnking*is sometng that I discovered entirely on my own last year, when Irealized that our textbook actually provided the *reasons* bend thevarious formulae we had all memorized in trig class.>Getting topics out of the way is not a good approach in general. To> really understand mathematics, you have to learn to let your mind> wander and explore. By being in a rush to pass advanced courses or> learn the coursework oftentimes students miss out on the deepness of> the material they study. Agreed. My biggest concern is not getting topics out of the way,but rather having sufficient background to begin such courses. Itnk I have a pretty good idea of what it takes to ace a course. Mybattle plan is sometng along the lines of:1) read the section of the textbook to be covered in the lecture*before* coming to class (in many cases several readings arenecessary); taking notes is also a good idea2) during the lecture, take notes but more importantly pay attentionand try to clarify whatever questions you had during your initialreading3) go home and try to piece together everytng learned from thetextbook and teacher. work through examples in the textbook, and doall assigned homework problems.4) make sure to clarify anytng you have trouble with. before thetest, do *extra* practice problems. Having supplementary textbooksaround is very useful.I wish I had carried out a plan such as ts beginning in, say, 8thgrade, but unfortunately I feel as if my understanding has some holesin it. I took my gh school's college prep geometry course in 9thgrade, wch omitted proofs entirely (fortunately I've introduced themto myself). There are a few holes I'm working on patcng fromAlgebra II. Trig is a little bit different, namely because I'm notentirely sure how much of it is really necessary. Identities, forexample: we've only used the Pythagorean, reciprocal, andtangent/cotangent identities in our calc class thus far. How muchtrig do I actually need to know for more advanced math?>Unfortunately, when you go to college, you may very well get> indoctrinated into ts way of doing tngs. It's important to learn> how to creatively learn mathematics before going to college, so as to> avoid ts trap. >When you get to college, you will want to become a member of the MAA. > Their periodicals are extremely helpful and will give you further> guidance. You may want to look at their publications, before> graduating. >Calculus is the initial hurdle of a college freshman, so it's a good> idea to have some familiarity with it. Someone has already recommended> Courant and Robbins, _What is Mathematics?_. It has a good section on> calculus that should cover what you need for now. Also, Gardner> has a revised version of Silvanus Thompson's _Calculus Made Easy_ that> I recommend. [Ts doesn't contradict my statements above, as even> Gardner notes that the title should really be Calculus made easier]I'm presently taking Calculus AB (calc ~ 1.5) at my gh school (ourschool does not offer Calculus BC). I'd say that I have asatisfactory *understanding* of the important concepts, my hurdle isfluency. I'm not exactly the brightest guy around, IQ somewhere inthe 120 range if that matters at all; 700 math SAT I score. I'mprobably the only student in my class who can explain the formaldefinition of the derivative, but tell me to differentiate somegod-awful trig expression and I'll most likely get lost in the mess. I ended up with a B+ in the course first semester, in part due to afew instances of rather poor planning that I intend on avoiding in thefuture.>As for what to do before going to college, play with math as much as> you can. There are lots of tngs to explore. You'll not have as much> time for playing in college.I hope so. I'm doing ts because I sincerely love math--I've read apretty good deal about some of the concepts of gher math, and theyreally intrigue me. I also realize that I'm not going to trulyunderstand these topics unless I put in a ton of hard work... how doyou get to Carnegie Hall? (if you didn't notice from my name ore-mail address, I'm a musician). At the same time, I'm not planningor expecting to become a full-blown mathematician. I'm an amateurcomputer programmer, and would ideally like to double-major in mathand CS, but I'm open to expand myself to other fields as well. AndI'm not entirely sure whether I have what it takes, in terms of rawintelligence, to survive as a math major, but I'm hoping that hardwork and genuine interest in the topic will prove to === future math majors? I'm a gh school senior planning on studying pure math as a major> ts fall in college. What I'm wondering is, what kind of advice> could those of you who have already been through the experienceoffer> to people in my position? What kind of background is necessary (or> recommended) to begin college mathematics courses, and what could a> future math major do in order to get a head start? Are there any> books or other information sources that would be helpful? Anyadvice> is greatly appreciated. If you haven't already, get some of the easier topics out of the wayby> studying on your own: linear algebra, probability, number theory, set> theory, as much calculus as you can stand. If you don't find thesetopics> easy, change to accounting. On the contrary, if you find these topics easy, you are undoubtedly> taking a very superficial view of them. Math is not easy, and the myth> that it is, is one of the big tngs a gh-schooler needs to dispell> when s/he goes to college.> Math has certainly never been easy for me, in part because I used to> learn it by rote like all too many people do. Mathematical *tnking*> is sometng that I discovered entirely on my own last year, when I> realized that our textbook actually provided the *reasons* bend the> various formulae we had all memorized in trig class. Getting topics out of the way is not a good approach in general. To> really understand mathematics, you have to learn to let your mind> wander and explore. By being in a rush to pass advanced courses or> learn the coursework oftentimes students miss out on the deepness of> the material they study.> Agreed. My biggest concern is not getting topics out of the way,> but rather having sufficient background to begin such courses. I> tnk I have a pretty good idea of what it takes to ace a course. My> battle plan is sometng along the lines of:> 1) read the section of the textbook to be covered in the lecture> *before* coming to class (in many cases several readings are> necessary); taking notes is also a good idea> 2) during the lecture, take notes but more importantly pay attention> and try to clarify whatever questions you had during your initial> reading> 3) go home and try to piece together everytng learned from the> textbook and teacher. work through examples in the textbook, and do> all assigned homework problems.> 4) make sure to clarify anytng you have trouble with. before the> test, do *extra* practice problems. Having supplementary textbooks> around is very useful.> I wish I had carried out a plan such as ts beginning in, say, 8th> grade, but unfortunately I feel as if my understanding has some holes> in it. I took my gh school's college prep geometry course in 9th> grade, wch omitted proofs entirely (fortunately I've introduced them> to myself). There are a few holes I'm working on patcng from> Algebra II. Trig is a little bit different, namely because I'm not> entirely sure how much of it is really necessary. Identities, for> example: we've only used the Pythagorean, reciprocal, and> tangent/cotangent identities in our calc class thus far. How much> trig do I actually need to know for more advanced math?My teacher put a lot of emphasis on trig identities... in my experience theyare useful for simplifying derivitives, and even more so integrals.So yes, they are good. You don't need to memorize a whole lot, but beingfamiliar with some of them and having experience proving them is good. Tryand find some problems wch have awful looking trig identities for you toprove... unfortunately, the only source I'm familiar with is an out of printrussian textbook, so I can't give you any advice on === Tutorial (Freeware) I don't tnk that there is anytng wrong with your notation. Well, let's face it Daryl, that's just an idiotic claim.> For example, it's extremely misleading to use | instead of the> connective v.> Who the did EVER write> p | q> when he MEANT> p v q or p / q or p or q> ???Somebody whose been taking CompSci for too many years?Honestly, I've done it before, particularly when I've been working onprogramming and then go to take a break. Of course, my scratch work containsall sorts of nonstandard symbols... :-/That said... well... I'll stay out of ts discussion ;-)> nt: The | usually is called the Sheffer stroke, and it is used to> denote the NAND truth-function.> http://www.swif.uniba.it/lei/foldop/foldoc.cgi?Sheffer+stroke> http://en.wikipedia.org/wiki/Sheffer_stroke> Don't tnk, look! === Give me that old time ontology: (was: the anticlassicalist }{ i: linguistic negation)> Why don't you state one single mind bogling factClassical propositional calculus has non-Booleanmodels! Related to ts and even more surprisingis that classical propositional calculus can bemodeled by a non-Boolean lattice [Reference 6], afact apparently overlooked for over 100 years!Common intuition is that classical propositionalcalculus and Boolean algebra go hand-in-hand.Lattice O6 is a counterexample that shows tsintuition is false.Ts is in http://teivos.samos.aegean.gr/~giorgosv/metamathsite/qlegif/ mmql.htmlreferencing:M. Pavicic and N. Megill,Non-Orthomodular Models for Both Standard Quantum Logicand Standard Classical Logic: Repercussions for QuantumComputers,Int. J. Theor. Phys. 39, 2349-2391 (2000),http://xxx.lanl.gov/abs/quant-ph/9906101 === fictional and that all of physics is built from either p-adics or doubly-infinites Re: infinite rightward strings tacked-on to p-adics serves as OrthogonalityI can tnk of several cases in physics where the idea that allnumbers come in only 2 types, either p-adics or doubly-infinites.wavefunction. And doubly-infinites as the surrounding wave or field....9999998 is surrounding by doubly-infinites of say for example.....999998.33333..... and .....9999998.5656565.... to mention justtwo.A second case is in the Lorentz transformations of Special Relativityx^2 + y^2 + z^2 - c^2t^2where the odd term is that of a negative signed c^2t^2. The terms ofx^2 and y^2 and z^2 are all p-adics but because the last term isnegative destroys the symmetry. But if we consider that the last termis a doubly-infinite whereas the first three terms are p-adics thenthe negative sign is removed. Also, the parameter of time maybe adoubly-infinite whereas the parameters of space are p-adics wchmeans that there are not really any 4th dimension and that dimensionsstop at 3rd dimension.The trd case deals with the incompatibility heretofor recognizedbetween thermodynamics, statistical mechanics and quantum mechanics inthe equipartition energy function. Perhaps those can be reconciledonce replacing some terms as p-adic and other terms asdoubly-infinites.The fourth case to consider is mathematics of e^i(pi) is -1. If weconsider that Reals are a fiction and that e and pi are doublyinfinites whereas i is a p-adic then we can manage to plug into thatequation actual numbers instead of symbols.And the endresult is not -1 since that is a Real, yet Reals are afiction and so -1 is really .....9999 in 10-adics. So all that isneeded is the doubly-infinite that is e and the doubly-infinite thatis pi.I cannot tnk of any cases in mathematics where a number system has 2components and where they are orthogonal to one another to resemble orsimulate the Doubly-Infinites.Arcmedes Plutoniumwhole entire Universe is just one big atom where dotsof the electron-dot-cloud are galaxies(www.iw.net/~a_plutonium) website of the science of AP under revisionwhat used to be my old science websitewww.newphys.se/elektromagnum/physics/LudwigPlutonium === a system consisting of 6 atoms. They all interact with one another(bonds and van der waals forces).I have the equations for the interactions between atoms.Each atom is in 3D space. I can alter the x,y,z for each atom.I will have a function that depends on these 3*6 variables. Constructingts function should be fairly easy.(For ease of work, I presume that I should fix one of the atoms at theorigin).I want to minimise ts function (analytically).So, How do I differentiate ts 18 variable function?I do have a degree in comp + math but it was a long time ago, and I don'teven know what ts would be called. Multivariate differentiation? Partialdifferentiation?Anyone know how to do ts (or have any links)Also, I've got some tools that I'll be using once I got the method straightin my head: Mathematica, mathcad and matlab.Anyone got any idea how I would use one of the packages to help me?(preferably mathematica, as I heard that the strongest symbolically) for any advice.Choca