mm-321 === Subject: : Re: Sphinx Tiling Explanation?>That's not the aperiodic tiling. Take the template used to make the>larger 16-sphinx shape from the unit sphinx, and use it to produce>a 256-sphinx (256 = 16^2) shape. Next, use the same template to produce>a 4096-sphinx shape out of 16 of those, next a 65536-sphinx shape,>a 1048576-sphinx shape, and so forth. As I see it, this ultimately>tiles only the upper half plane, so a mirror image (or 180 degree>rotation) would be needed as well, to fill in the entire plane.Surely you don't need this reflection if you just perform the recursioncentred about the uppermost upright (magenta) sphinx, rather than any ofthe four on the bottom row? -- Erick=== === Subject: : Re: Sphinx Tiling Explanation?True, you can extend the sphinx in any direction at any time, but thenyou can't guarantee that you have an infinite line of unit sphinxes, andthen if you don't have such a line, it's much harder (if not impossible)to guarantee that it's aperiodic.Justin: Surely you don't need this reflection if you just perform the recursion: centred about the uppermost upright (magenta) sphinx, rather than any of: the four on the bottom row?: -- Erick=== === Subject: : Re: Turing machine question> A Turing machine question:> Can you build a Turing machine if - instead of a pen and an> eraser to mark on the tape you have a *finite* number of paper> clips, which can be clipped on and off the tape?You could certainly build such a machine, but its power, as,say, a language recognizer, would be severly limi. Therewould certainly be useful things such a machine could do--unary addition is just one example. > You could not use binary representations - you would have> to use large numbers to store things - stored in the form:> 1: .X> 2: ..X> ...> 50: ..................................................X> ...etc.Of course you could use binary representation: 0: .X 1: .XX 2: ..X 3: .XXX 4: .X.X ... 50: ..XX..X > If the answer is no, then why not?If you star out with a fixed number C of clips,your machine would not even be capable of recognizingall regular languages, since many regular languagescontain strings of length greater than C, so youwouldn't even be able to represent some inputs.If, on the other hand, the number of clips you coulduse was O(n) for inputs of length n a quick guessmight be that your proposed machine might be ableto recognize all context-sensitive languages, thoughI really haven't given this much thought.Rick=== === Subject: : Re: Turing machine question 3QLpj-NoP*NzsIC,boYU]bQ]H'y<#4ga3$21:> A Turing machine question:> Can you build a Turing machine if - instead of a pen and an> eraser to mark on the tape you have a *finite* number of paper> clips, which can be clipped on and off the tape?>> You could certainly build such a machine, but its power, as,> say, a language recognizer, would be severly limi. There> would certainly be useful things such a machine could do--> unary addition is just one example.The power would not be severely limi unless you mean merely that it would be slower. Two-counter machines are capable of simulating arbitrary Turing machines. If you can distinguish some position on the tape (say the start of the input) then two paper clips are enough to simulate two counters, by their distance from the distinguished position; otherwise you could use three paper clips.-- David Eppstein http://www.ics.uci.edu/~eppstein/Univ. of California, Irvine, School of Information & Computer Science=== === Subject: : Re: Turing machine question>A Turing machine question:>>Can you build a Turing machine if - instead of a pen and an>eraser to mark on the tape you have a *finite* number of paper>clips, which can be clipped on and off the tape?>>You could certainly build such a machine, but its power, as,>>say, a language recognizer, would be severly limi. There>>would certainly be useful things such a machine could do-->>unary addition is just one example.> The power would not be severely limi unless you mean merely that it > would be slower. Two-counter machines are capable of simulating > arbitrary Turing machines. If you can distinguish some position on the > tape (say the start of the input) then two paper clips are enough to > simulate two counters, by their distance from the distinguished > position; otherwise you could use three paper clips.Ho ho. Of course you're right. Looks like I made the samesort of mistake I warn my students about--assuming that*a* mental model is *the only* one.Rick === === Subject: : Re: Turing machine question>> A Turing machine question: Can you build a Turing machine if - instead of a pen and an>> eraser to mark on the tape you have a *finite* number of paper>> clips, which can be clipped on and off the tape?>> You could certainly build such a machine, but its power, as,>> say, a language recognizer, would be severly limi. There>> would certainly be useful things such a machine could do-->> unary addition is just one example.> The power would not be severely limi unless you mean merely that it > would be slower. Two-counter machines are capable of simulating > arbitrary Turing machines. [...]Thanks - this and Minsky machines proved to be useful search terms.-- __________ |im |yler http://timtyler.org/ tim@tt1lock.org Remove lock to reply.=== === Subject: : Re: Image of a straight line in a convex cylindrical mirror> In 3D, y+b=0 is a plane. Right? Are you looking for its reflection, or> reflection of a line?> What is the reflection in a cylindrical mirror x^2+y^2 = a^2 of a> straight line y+b = 0 as seen from a viewpoint (0,-c,h) ( a < b << c)> ? Is it a catenary ? If not, what is it?> It's probably safe to assume, since this is a line on the floor of the> mall, that the equation is y+b = 0 and z = 0. Now that it's been a few> days, can I give a hint? The symmetry of the problem -- what> coordinate system should you be using?Looking for the reflection of line y+b=0,z=0, an omit typo. Shouldbe using polar/cylindrical (r-th-z) coordinates for convenience ofsymmetry.=== === Subject: : Re: Image of a straight line in a convex cylindrical mirror> In 3D, y+b=0 is a plane. Right? Are you looking for its reflection, or> reflection of a line?Looking for the reflection of line y+b=0,z=0, omit typo.=== === Subject: : conjugate subgroupsWhy can't a conjugate of a subgroup be a proper subset of it?=== === Subject: : Re: conjugate subgroups> Why can't a conjugate of a subgroup be a proper subset of it?Because if H is a subgroup of G, h in H and g in G with gHg' asubset of H, then g'Hg is also a subset of H. What does thatimply about the equation gkg'=h?=== === Subject: : Re: conjugate subgroups> Why can't a conjugate of a subgroup be a proper subset of it?> Because if H is a subgroup of G, h in H and g in G with gHg' a> subset of H, then g'Hg is also a subset of H. You sure? I would have thought a superset, not a subset.> What does that> imply about the equation gkg'=h?=== === Subject: : Re: conjugate subgroups>> Why can't a conjugate of a subgroup be a proper subset of it?>> Because if H is a subgroup of G, h in H and g in G with gHg' a>> subset of H, then g'Hg is also a subset of H. > You sure? I would have thought a superset, not a subset.Well, I may have been sure, but as several posters have poin out, I was also wrong. >> What does that>> imply about the equation gkg'=h?=== === Subject: : Re: conjugate subgroups>> Why can't a conjugate of a subgroup be a proper subset of it?It can!>Because if H is a subgroup of G, h in H and g in G with gHg' a>subset of H, then g'Hg is also a subset of H.That's not true. Take H cyclic subgroup of GL(2,Q) genera byh = ( 1 1 ), ( 0 1 )and let g = ( 2 0 ) ( 0 1 )ghg^-1 = h^2 but g^-1hg = ( 1 1/2 ) ( 0 1 )Derek Holt.> What does that>imply about the equation gkg'=h?=== === Subject: : Re: conjugate subgroups> Why can't a conjugate of a subgroup be a proper subset of it?Surely it can (consider the subgroup genera by the matrix (Mathematica notation) {{1,1},{0,1}} inside GL_2(Q)). Why do you ask?Jyrki Lahtonen, Turku, Finland=== === Subject: : Re: conjugate subgroups> Why can't a conjugate of a subgroup be a proper subset of it?> Surely it can (consider the subgroup genera by the matrix > (Mathematica notation) {{1,1},{0,1}} inside GL_2(Q)). Why do you ask?> Jyrki Lahtonen, Turku, FinlandYes, I realized the result was false shortly after posting. This meansthere is an error in Spanier's Algebraic Topology, p. 74. There heclaims that two subgroups of a group are equal because they areconjugate and one is a subset of the other, but actually they areequal for a different reason.=== === Subject: : Re: conjugate subgroupsWhy can't a conjugate of a subgroup be a proper subset of it?> Yes, I realized the result was false shortly after posting. This means> there is an error in Spanier's Algebraic Topology, p. 74. There he> claims that two subgroups of a group are equal because they are> conjugate and one is a subset of the other, but actually they are> equal for a different reason.Sorry, but which chapter, section, etc is that? I only have the Tata-McGraw hillpaperback edition available, and there p.74 is at the beginning of section 4of chapter 2 (section titled The Lifting Problem). I couldn't immediatelylocate the claim you mentioned on that page or any other page near it.Jyrki=== === Subject: : Re: conjugate subgroupsWhy can't a conjugate of a subgroup be a proper subset of it?> Yes, I realized the result was false shortly after posting. This means> there is an error in Spanier's Algebraic Topology, p. 74. There he> claims that two subgroups of a group are equal because they are> conjugate and one is a subset of the other, but actually they are> equal for a different reason.> Sorry, but which chapter, section, etc is that? I only have the Tata-McGraw hill> paperback edition available, and there p.74 is at the beginning of section 4> of chapter 2 (section titled The Lifting Problem). I couldn't immediately> locate the claim you mentioned on that page or any other page near it.> JyrkiChap. 2, Sec. 3, Theorem 11=== === Subject: : Re: Basic factorization ideasIn sci.physics, <3c65f87.0311120854.6eb55db1@ posting.google.com>:>> In sci.physics, >> <3c65f87.0311111302.799cf8e3@posting.google.com>:>> If you saw (c_1 x + 7)(c_2 x + 7)( c_3 x + 1) = > 49(x^3 + 5x^2 + 3x + 1) with the c's algebraic integers, I think few of you would have a>> problem realizing that only two of the c's have 7 as a factor.>> Oh, look, he's changed polys on us! But OK, let's check>> this one.>> Recall that, if P(x) = 49 * (x - x_1) * (x - x_2) * (x - x_3),>> then P(x) = (c_1 * x + 7) * (c_2 * x + 7) * ( c_3 * x + 1)>> implies that c_1 = -7 / x_1, c_2 = -7 / x_2, c_3 = -1 / x_3,>> for some permutation of the x_i. Again, c_1 * c_2 * c_3 = 49,>> as required, since x_1 * x_2 * x_3 = -1.>> Therefore, c_1 and c_2 both satisfy the equation>> c^3 * P(-7 / c)/49 = c^3 - 21*c^2 + 245*c - 343>> and c_3 of course satisfies>> c^3 * P(-1 / c)/49 = c^3 - 3*c^2 + 5*c - 1>> so it turns out that this time, James, you got it more>> or less right. (And c_3 is even a unit, to boot.>> Come to think of it, so are the x_i, which is probably>> one big reason why this particular case actually works.)>> Also, it is obvious that c_1 and c_2 have factors of 7,>> as well, in the ring of algebraic integers. But, of course, you're looking at *functions* of x, as you have f_1(x) = c_1 x, f_2(x) = c_2 x, and f_3(x) = c_3 x, so I could also write it as >> (f_1(x) + 7)(f_2(x) + 7)( f_3(x) + 1) = 49(x^3 + 5 x^2 + 3x + 1). Notice that dividing both sides by 49 gives (f_1(x)/7 + 1)(f_2(x)/7 + 1)( f_3(x) + 1) = x^3 + 5 x^2 + 3x + 1 as long as you're in a ring where 7 is not a factor of 22.>> OK, stupid question. Where did the 22 come from?> Oh, I've been used to arguing with people about> (5 a_1(x) + 7)(5 a_2(x)+ 7)(5 b_3(x) + 22) => 49(300125 x^3 - 18375 x^2 - 360 x + 22)> where the a's are roots of> a^3 + 3(-1 + 49x)a^2 - 49(2401 x^3 - 147 x^2 + 3x)> and b_3(x) = a_3(x) - 3, which is a substitution made because a_3(0) => 3, so that I can isolate constant terms.> My point is that certain rules apply as even with my example above, I> just have rather basic functions of x.Great. Try your logic on this polynomial.(c_1 x + 7)(c_2 x + 7)( c_3 x + 8) = 49 * (x^3 + 8).If you don't like that one, try this one:(c_1 x + 7)(c_2 x + 7)( c_3 x + 2) = 49 * (x^3 + 2).>> But yes, for this particular example, your odd math actually does>> work, as you are dealing with x_i which are in fact units.> So you believe that math is quirky?Your math sure is.[rest snipped]-- #191, ewill3@earthlink.netIt's still legal to go .sigless.=== === Subject: : Faustus of Witten-burgMusic from Gounod's Fausthttp://www.classicalarchives.com/m/023/act_1_du.midplay the above in background as you read like the piano in a silent movieat the Nickelodeon 100 + years ago on the New York City Bowery.Z as MephistophelesMe as Dr. FaustusPaul, all my books are packed ready to move so I cannot get the precise formulaI remember. Basically though you can split the torsion-free Levi-Civitaconnection for parallel transport of tensors (Lie dragging along vectorfields) along world lines in curved base spacetime of the tangent bundlein terms of a bona-fide 3rd rank Diff(4) group tensor + the inhomogeneousnon-tensor part that causes all the trouble in the gravity vacuum issue ofa local stress-energy density tensor.All the above is from the local gauging of the energy-momentum Pugenerators of the 4-parameter translation sub-group of the 15-parameterConformal Group.Locally gauge the 6-parameter O(1,3) subgroup of the Conformal Groupin the tangent space to get the torsion fields which appear as anew Diff(4) 3rd rank tensor addition to the connection that isanti-symmetric in two of the indices.According to Tony Smith, Segal locally gauged the remaining 5 parametersub-group and I think that should be unified exotic vacuum dark energy/matter.That is only a wild guess at this stage. I have not worked that out yet.Fast ForwardM-theory may be the final proof of the bankruptcy and heuristicexhaustion of theformal-empirical methods of modern physics. On the other hand, underthe rightinterpretation, it might open up new vistas. We'll see.No argument from me on that one! What a double standard eh? -- abouthype in science I mean.People are always telling me to connect my theories with experimentsand observations. Wellthat's what I have done more so that anything on NOVA's ElegantUniverse although I doconnect my math with their stringy alpha' and indeed I think what Ihave done inhttp://qedcorp.com/APS/EmergentGravity.pdf is good for Witten & Co Ihave connec theirvaporware more closely to observations of important stuff like thecosmological constant.Z: Well, of course there has to be an empirical bottom line -- cash value.Let me suggest that the biggest payoff -- and the best potential sales point for yourprogram -- would be the prediction of *novel phenomena*, which only a newfundamental theory of gravitation of the kind you are offering is likely to be capableof.Dark Energy/Matter IS that! It's as novel as they come. Mike Turner and Ed Wittenadmit readily in print they really have no clue at all! They are honest men. Untilshown otherwise I think I have the correct explanation. Also UFOs are novelphenomena, but try getting that into Nature!Don't forget Regge trajectories, stability of electron (evaded by string theorists)and point structure of lepto-quarks in deep inelastic scattering. I got plenty ofphenomena.Of course it is the string tension that stabilizes the self-electric chargebut what is the origin of that tension? It is dark matter /zpf < 0 exotic vacuumnegative zero point energy density with positive pressure that doesthe trick providing the mechanism for the string tension or micro-geonquasi Kerr Newman black hole where the extra space-dimensions providethe strong and electro-weak charges. The micro-black holes have hairin hyperspace.Also the open end strings can connect different branes not just the same brane.I think the branes come from O(N) symmetries of the MACRO-QUANTUMorder parameter beyond my approximate O(2) model that makes quantized string topological defects in 3Dspace from imposing single-valuedness on the local vacuum coherence field PSI.Giant Star Gates stabilized by exotic vacuum dark energy /zpf > 0also connect different brane parallel worlds floating in hyperspace.This is the UFO phenomenon.Z: But the extravagant resort to these multi-dimensional hyperspaceslooks verysuspicious to me -- regardless of how neatly the Standard Model fitsinto theformalism.Pythagorism run amuck?In any case, Puthoff is not claiming that his PV theory is any kind offundamentaltheory of gravitation -- just a highly computable working model thatmight beat least pragmatically justified by some future deeper theory.Not so, I think he claims he has a viable alternative to Einstein.Z: I never read that from him. He issued repea disclaimers that PV was not atthe present stage of the game to be regarded as anything more than anengineering model.We must have read different things. Puthoff, for example, claims there are no black holes, no event horizons.Z: Although he did say that *if* the Yilmaz theory or some other field theory thatrecovers his exponential metric expansion is eventually vindica, then that*could* provide a deeper justification for his model.But even then PV would not reach down as far as quantum gravity, obviously.That is unless an empirically valida Yilmaz-type field can be and is successfullyquantized.I think Hal's approach violates Einstein's Rule:Make physics as simple as possible, but not simpler than is possible.Ditto for Evan Harris Walker's.Z: Your original strategy, as I understand it, was to piggyback your BEC modelby way of correspondence (emergence) on canonical GR as expounded in MTW,and on the authority of their big black bible.NO! My approach comes from the following sources:1. Andrei Sakharov's metric elasticity2. P. W. Anderson's More is different3. Hagen Kleinert's world crystal lattice 4D elastic-plastic formulationof Einstein's gravity allowing torsion in addition to curvature.4. Bohm's pilot-wave/hidden variable interpretation.5. Wheeler's IT FROM BIT and his early Geometrodynamics ofMass without mass, Charge without charge, Spin without spinWheeler's idea here came from Einstein's Vision6. Feynman's inability to solve electron self-energy/self-charge problemapart from the shell game (his term) of renormalization.7. Unrenormalizability of Einstein's classical gravity made into a localquantum field theory by standard methods.8. Regge data in hadrons.9. Point structure of lepto-quarks in deep inelastic scattering.10. Dark energy/matter as 95% of the Universe.Z: If I am right and MTW are the Enron of gravitational physics, then I would saythis is a serious mistake.You are not right.Z: If I am right, then your best strategy would be to consistently and explicitly breakwith the naive Einstein interpretation of the EEP and look for a radically differentcorrespondence model vis a vis a consistently re-interpre GR.I have already done it. Do you not understand what I am saying?Z: As I see it, that would entail a meta-theoretic mapping of your Goldstone phase to aseparate physical metric that represents the phenomenological g-field.I do not understand what your words mean? I have the equations written down inhttp://qedcorp.com/APS/EmergentGravity.docDo you have different equations to replace them?Without math I simply do not understand what you are saying here. What difference does it make?As far as I am concerned the local classical vacuum stress-energy density Diff(4) tensor is simplytuv(vac) = (c^4/8piG)GuvEinstein's local field equation in non-exotic vacuum is thentuv(classical vac) + Tuv(matter-radiation) = 0Adding exotic vacuum dark energy/matter istuv(classical vac) + tuv(quantum zero point) + Tuv(matter-radiation) = 0tuv(quantum zero point) = (c^4/8piG)/zpfguv/zpf = (alpha')^-1[(alpha')^3/2|Vacuum Coherence|^2 - 1]alpha' = Witten's string parameterD^uDu(Vacuum Coherence) + dU(Vacuum Coherence)/d(Vacuum Coherence*) = 0 is Landau-Ginzburg eq. BIT FROM ITdu(x) = alpha'(Goldstone phase of Vacuum Coherence),u is IT FROM BITguv(x) = Minkowski + du,v(x) + dv,u(x)BIT is Vacuum Coherence = The Wordguv and /zpf are IT = The Fleshif you want to decode The Cipher of Genesis or The Da Vinci Code - the real one not the fake one. http://qedcorp.com/APS/StarGate1.mov(typo correc yesterday on dark matter slide)Z: You would then of course also have to recover the inertial metric, but you wouldfuse this with the gravitational metric at the correspondence level, and not on themost fundamental theoretic level.Ditto. I do not understand what you mean.Z: Your theory could then provide a physical basis -- based on your virtual BECcoherence -- for the *limi* physical analogy between gravitational and inertial fields.Not could but doesZ: While you seem to be on the right track with your emergence thesis, I don'tthink you are as yet entirely consistent in your approach, for the fundamentalreasons I have sta.I do not understand your reasons and I never will as long as you rely totally onvague ambiguous ordinary language without mathematics and/or precise operationalgedankenexperiments like in the Einstein-Bohr Dialogues.Z: As for elegance -- as Boltzmann once said, when in the process of lookingfor deeper models of physical reality, elegance is for tailors.I honestly don't understand why you think you are in directcompetition with Hal.Because he got all the money people in the fringe BPP people to thinkhe is on theright path - not that there is a lot of money there. But because of hispast top securityclearances he has influence and access inside USG Black Ops and in factthere is afactional fight inside USG right now about all this - more than that Icannot say. So theissue is one of whistle blowing on wasting tax payer money on thingsthat have nochance of working whilst ignoring things that do.Z: OK -- now that makes sense.I'm not sure we're on the same page here. But I *am* talking aboutspinningEinstein equivalence-- within the framework of canonical GR.space-time. It's complica butstandard in MTW et-al.Z: And does he mention any empirically testable scale-independent multipoleeffects?If so I'll have a look at that.Don't know off hand.If ALSO there is TORSION then additional coupling of spinning testZ: OK, but that's another ball game.Is there any convincing empirical evidence for non-vanishing torsion?Good question. Akimov in Moscow says so. Looking at Kleinert it wouldbe strange if it were not there. How big ? is the issue.Akimov in Moscow says that is a big effect with weapons applications.One guy here who came to ISSO 2000 also said that and he was working onareport. Most researchers pooh pooh that. I do not knowfirst-hand.Z: I said convincing. Apply same standard to Brian Greene's Elegant Universe.String theory is like 2D field theory because the string sweeps out aworld sheet in ordinary space-time rather than the 1D world line. Thisis a great thing because it essentially does away with the infinitiesCosmological Constant problem, which worries Witten and rightly so.problems.NO! String theory give bad prediction /zpg = 10^66 cm^-2 whenexperiment says/zpf = 10^-56 cm^-2 because Witten's strings are only 10^-33 cm asBrian Greenerepeats many times in the NOVA vaporware.String theory is no better than local field theory on this issue! Wellonly a little better, butstill 122 Powers of Ten off-target!Witten understands that!They lack my giant vacuum coherent field!Z: No? So I am wrong to think that string theory avoids all the renormalizationheadaches of QFT at least partly because it posits extended entities as modelsYou have garbled renormalization with the cosmological constant.String theory does avoid the infinite renormalization constants offinite numbers. The string theory prediction for the Einsteincosmological constant is/ ~ 1/Lp^2 ~ alpha'^-1 = 10^66 cm^-2In contrast observation is/ ~ (Ho/c)^2 = 10^-56 cm^-2That's why Ed Witten the smartest man in physics today according to Brian Greene on NOVA Elegant Universe so so worried about it!My solution to that problem is simply/ = alpha'[alpha'^3/2|Vacuum Coherence|^2 - 1]Where alpha' is Witten's favorite thing (string tension)^-1 = c^4/G*What none of the Pundits have from Witten to Puthoff (that's many powers of ten in mathematical depth ) is VACUUM COHERENCE!IMHO.http://qedcorp.com/APS/EmergentGravity.docZ: OK, I'll read it.After all - you get an infinite mass density and infinite electricalforces insidegravitationalforce is infinite at zero separation of two mass points.The classical electron was a hopeless conundrum even in Lorentz'stheory.THIS IS NOT THE PROBLEM.Z: I know you are talking about exploding perturbation expansions, massrenormalization, that kind of thing. If these go away under a string model,I imagine the extended nature of the model might be relevant to the problem.But then, what do I know?imprecise and ambiguous - goodfor poetry not for physics.Z:Your simple dichotomy between ordinary words and math is a falseone IMO.There is ordinary language, there is *technical* and *scientific*language, andthere is the highly refined and abstract language of naturalosophy.Then there is mathematics.If the formal mathematics is to have a well-defined physical meaning-- a physicalinterpretation -- then it must be arrived at and expressed inextra-mathematical technicaland osophical language.Even Einstein had an equivalence principle -- expressed in what youcall ordinarylanguage -- before he had the Einstein-Hilbert field equations andbefore he even hada metric tensor representation of the g-field.Yet we still don't know what these field equations mean exactly,except in purelyformal-empirical terms, since Einstein's equivalence principle isproblematic.I do not mean that ordinary language is not useful or important. Imean't that it is not enough.Z: And of course in that case I completely agree with you.Einstein had math to back up his essential points inordinary language.Z: Of course. But the math is for the most part standard and almost completely workedout. We have the canonical theory, with the EEP, and a raft of bi-metric theories.The problem on this level, as I see it, is for the most part finding the correct physicalinterpretation of the math that is already available.Which, incidentally, and perhaps ironically, is precisely how Einstein arrived atspecial relativity. After Lorentz and Poincare, he took the last *interpretive* steps.After all, they are called the *Lorentz* transformations -- and not the Einsteintransformations.What I have to do is show that when you back out the non-tensor inertial contributionto the vacuum gravitational stress-energy density, you get something that transformslocally like a world-tensor (under Diff(4)) .My solution is simplytuv(classical geometry) = (c^4/8piG)GuvZ: That could begin to make sense of the theory of gravitational waves, which is currentlya puzzle within a puzzle. Anyone who claims to understand it obviously doesn't.I have to start with the standard weak-field (linearized) model and go from there.When I have finally done this I'll write it up and then you can read all about it.I am not going to write anything until I have the math completely worked out.I think Kip Thorne correctly worked all that out in the LIGO/LISA project.Do not reinvent the wheel. I doubt you can do it better than Kip Thorne & Co.So far, I am not aware of even ONE math formula to back up any of yourkey points that you have expressed so far only in ordinary informallanguage.Am I mistaken here? Please correct me if I missed something. We havebeen goingback and forth on this for almost 2 years now without any relevant mathfrom your corner.Actually, the basic mathematical approach is easy. You just locally separate the inertialand gravitational contributions to the metric gradients:g_uv, w = g_uv, w |G + g_uv, w |I, for all u, v, and w.(Here G = Gravitational, I = Inertial)Then the gammas automatically decompose in an analogous manner.I do not see what those terms are.I think you are wrong here.guv is a tensor.The place to start is the connection like I did above.Apart from my formulaguv = Minkowski + World Crystal Strain Tensorthere is nothing new here.Z: I am looking for a theorem in differential geometry that locally splits the deformationaland transformational contributions of the metric gradients on an abstract curved4-dim Riemannian manifold.That's eqs (1.5) & (II.2) & (II.3) inhttp://qedcorp.com/APS/EmergentGravity.docZ: I've just been busy with other things, but I'll get down to it eventually.It would be different if I were getting money to do it.I have already done it.Z: The physical stress energy (of the permanent field) can then be construcout of gammas from which the g_uv, w |I have been removed.No, because the gammas are zero in the LIF.Z: The only thing that makes the vacuum stress-energy a pseudo-tensor, as far asI can see, is the inertial contribution to the gammas.You mean the non-tensor term in the gamma. They mix with the tensor term when you makea quadratic form in the the gammas. I fail to see how that gets one anywhere.tuv(geometry) = (c^4/8piG)Guvsolves the problem trivially because it is a trivial problem IMHO.The Question is: What is the The Question?Z: At this point the math is pretty straightforward. What is important is what it *means*in the context of GR.Then write it down.Z: What it *means* is that without Einstein equivalence there is no such thing as generalrelativity. It's a mirage. That also raises serious questions about *special relativity*.And I am NOT a crank....Uh Oh!Einstein's equivalence principle is classical and the boundary of itsdomain of validity isfuzzy and problematical, which is part of its greatness like great Artand Poetry.Z: Yes, and of course I agree. I'm not in the business of trashing dear old Albertfor the sake of it.Like some we know.Z: But I suspect you are here talking about the EEP. I say Einstein equivalenceis in fact invalid *everywhere*. But if you are only talking about EEP, then I agree.In any case, as to Einstein equivalence, that is what I mean when I use the termheuristic. This is of course all very important in the context of discovery,even if it does eventually turn out to be a red herring.But I am working in the context of evaluationFor example the classical Einstein equivalence principle and thequantum Heisenberguncertainty principle work hand in hand to produce the randommicro-quantumDiff(4) covariant additional term /zpf(x)guv(x) in Einstein's localfield equation.See John Peacock's Cosmological Physics pp 25-6 for that derivation.Z: My guess is that this is a formalistic grafting of some of QM (which no oneunderstands) onto GR (which almost no one understands).It leads to the very nice eq. (III.1) inhttp://qedcorp.com/APS/EmergentGravity.docEinstein's equivalence principle has a nice mathematical expression inthe tetradtransformationFLAT SPACE-TIME = TETRAD (CURVED SPACE-TIME)and inverselye.g.nab = ea^u(P)eb^v(P)guv(P)Z: As an expression of the bare EEP, yes.Yes yes yes.Will you take yes for an answer?That's all I ever need and use.Z: But this is still no more than a mathematical re-packaging of the EEP. It adds no newphysical content.It sure does and it's all inhttp://qedcorp.com/APS/EmergentGravity.docplain as day.Z: And it still does not in and of itself fully capture the content of Einstein equivalence,which reaches much deeper than the formal-empirical level of the EEP.As far as I can see the math of the point you are making is thatTORSION-FREE CONNECTION = HOMOGENEOUS 3rd RANK TENSOR + INHOMOGENEOUSPIECESo your inertial field is the second piece on RHS.Z: Yes, exactly. If you interpret this inhomogeneous piece as a kinematical field.Fine.Z: The idea is that if you pull this out of the connection field, what you have left is much morelike a classical field, although it is represen by tensor quantities and integrates rubberrod and clock metric effects with forcelike dynamical effects.*That* is what a deeper theory should recover based squarely on a physical model.I do that in http://qedcorp.com/APS/EmergentGravity.docZ: And it will, if I am right, also have a fully localizable vacuum stress-energy which transformsmuch more like the EM stress-energy under Diff(4) in both weak- and strong-field domains.Again that's simply in the Wittenesque symbology of the real Da Vinci Code [What is the alpha in Egyptian hieroglyphs and Babylonian cuniform? Is alpha the Aleph? No it's clearly the Bayt (bait)]tuv(vac) = (c^4/G*)[Guv(classical Einstein) + /zpfguv]= (alpha')^-1 [Guv(classical Einstein) + /zpfguv] = (String Tension)xCurvature(MACRO-QUANTUM + Micro-Quantum Zero Point)What more is there to be said here? It's in the standard Einsteintheory.Z: But again, that is *not* Einstein's theory.Let's not quibble. None of this would be in discussion if Einstein never exis.Z: With all due respect Jack, you do not seem to know what Einstein's theory actuallywas!What *you* mean by general relativity is not what *Einstein* meant by general relativity.With different punctuation, what *you* mean by general relativity (at least on Mondays,Wednesdays, and Fridays) is *not general relativity*.I have already given you fully adequate documentation on this.Power-down reset?But in any case, I actually agree with *your* current definition, since Einstein's generalrelativity doesn't exist.As long as you adhere to it consistently.You are splitting very fine hairs here. No mainstream physicist doing perfectly good work inprecision cosmology would understand you here or even care to.One can quibble about the informal language attached to this formula,but I think it is a quibble.Z: You are saying that refutation of Einstein's fundamental argument for the general relativity ofall motion -- which he himself protes was the very cornerstone of his theory of gravitation-- is a quibble?Jack, pull the other one.No, I did not say that. You did.The main content of Einstein's theory, the key algorithm, isGuv = alpha'Tuvwhat he may or may not have said in heuristic informal language at some early point in the emergence of the theory is not that important.EEP here also means that locally at event P one can find timelikegeodesic frames in which theTORSION-FREE CONNECTION = 0 at P but not in neighborhood of P whentensor curvature =/= 0 at P.Z: OK.What gyroscopes do if there is a torsion field was not considered inEinstein's original theory.Z: He ruled out any empirically measurable effects that would locally distinguish gravitationaland inertial fields. In this sense, he did consider them as belonging to a class of possible effectsthat were prohibi by his equivalence principle, which was supposed to hold -- and indeedhad to hold -- universally and without restriction.No he did not later on in his unified field theory later period.No principle in physics holds universally without restriction. What Einstein said in 1915pre 1925 on this should not be taken literally. See Bohm on this BTW.But that is a straight forward extension.Einstein's theory guv(P) is from locally gauging the LINEARTRANSLATIONS inCONFORMAL = DILATION x NONLINEAR SPECIAL TRANSLATIONS x LINEARTRANSLATIONS x SPACE-TIME ROTATIONSTORSION is local compensating gauge field from SPACE-TIME ROTATIONS.We should LOCALLY GAUGE EVERYTHING! Why stop at a subgroup?Z: More Pythagorean groupology!It works.Z: Where's the beef?Yum, yum. Niman not Wendy's.The torsion-free connection can probably be split into the homogeneoustensor part + the inhomogeneous part.Indeed I remember that and can quickly look it up. So if that is allyou mean, then that is standard Einstein.What then is the point here?That's not it. The decomposition I am talking about is orthogonal tothis.I have no idea of what you mean here if you cannot produce a mathformula togive the informal sentence meaning.See above.I have explained the point many times. We are separating the inertialand gravitationalcontributions to the connection field.You have explained nothing to my mind unless there is math to give thewords meaning and/ora precise operational gedankenexperiment in sense of theBohr-Einstein debates.See above.Also, showing how your new insight predicts some new physics and/orexplains animportant mystery in the old physics is also desired.It's not new, and it's not mine.(1) The equivalence principle is a mere conjecture that is not to be taken too seriously;(2) The GR inertial field is associa with a stress-energy density that is a non-tensor.That was *1922*.Einstein had a slugfest with von Laue in the early 20s on this, in which von Laue arguedfor the purely heuristic character of Einstein's principle.gradients g_uv, w asmetric potentials of the [permanent] gravitational field.Bergmann also referred to a pure inertial stress-energy.Feynman more or less trashed Einstein equivalence in the 60s.Precise quotes please.Z In the 90s Weinberg announced in his Gravitation and Cosmology that he isa heretic.Ditto.Z: I am just trying to push this skeptical argument to its logical conclusions.I gather deformational means Ruvwl curvature tensor =/= 0 at P ?It means the contribution to the connection field (i.e. metricgradients) that resultsfrom the deformation of the spacetime manifold, where Ruvwl =/= 0.Transformational is when Ruvwl = 0?It's what you have left when you set Ruvwl = 0. It is obviously stillpresent even when Ruvwl =/= 0 in almost all frames.Fine.OK.I think that is what I said above. It's already there in Einstein'soriginal theory. Nothing new here IMHO.Z: Of course this is not new. It is the (logical) conclusions that I am drawing from it thatare new.Yet I wonder: Why does Weinberg feel compelled to call himself a heretic when heis writing about this in the mid-1990s?If it's all so standard and obvious??Feynman and Weinberg quotes would help here.Z: This is really a matter of pure differential geometry, since itholdsgenerally in theabstract, without any specific reference to spacetime manifolds.I do not understandwhat you mean by inertial compensation above.Z: Just think of how inertial and electrical forces interact and howthisis describedmathematically in *standard GR*. The EM field is notgeometrodynamic,while thepure inertial field (no gravitational sources) is.EM field is geometrodynamical in Kaluza-Klein with one extra spacedimension.Z: That's not *standard GR*, JackZ: Are you telling me that Kaluza-Klein is now canonical? Or are youtalking aboutsuperstring theory?Yes, in sense there is well-defined math meaning to their concepts,which is lacking inmost of your thesis here unless I have missed something specific?Z: The math is for the most part completely standard.It is the interpretive conclusions that are new.I think the fictitious or inertial g-force i.e. the metrictorsion-free connection for parallel transport in the original1915theory is LOCALLY equivalent to agravity force.Z: Einstein's principle was that a uniform gravitational field is*fundamentallyindistinguishable* from an inertial field. That is all in thehistorical record.Depends what one means by fundamentally.Z: It is quite clear what Einstein meant. He was quite forthcoming onthis. I think it's important to recognize that this is the cornerstone ofEinstein'sconcept of general relativity. The meaning of Einstein's principle isquiteunambiguous when placed in context.Fine, but nothing wrong with what Einstein said above except thatphysically we never havea global uniform gravity field.Z: There is nothing wrong with it except that it is almost certainlyfalse as a matterof empirical fact.Yes,Z: Stop right there!Yes.So you actually agree with me.Einstein was playing with a useful idealization, theorists do that all the time. It led to the correct conception. It's like the principle of virtual work.Remember without electromagnetism no light hence no gravity!First:Let there be lightGravity came on the Second Day.Decoding The Cipher of Genesis.but one could imagine a universe like that in terms of theparameters of the theory.Z: One could.I'm interes in this universe.Although I agree that Einstein was at least consistent -- which I cannot say for MTW.Einstein had to pretend that while Riemann curvature distinguishesalmostall permanent gravitational fields (Eddington, Tolman, Bergmann)from all inertialfields, it has no direct physical meaning, at least in the immediateneighborhoodof a spacetime point.No, again I think you are mis-interpreting here.If the local curvature is not zero it is not zero in any frame at P.Z: Yes...However, it'stidal effect at P is ignorable in a small enough neighborhood of Pprovided1. Not near a space-time singularity2. Not inside the effective Planck area Lp*^2Z: Isn't that like arguing that since we cannot measure Gaussian curvature at ageometric point, the Earth is really flat there?No, we can measure it at a coarse-grained point determined by band width ofthe detectors.Z: So is that a flat-earth argument?No.Z: Or pseudo-positivistic gobbledygook?No, that's physics not shmizziks.Z: The Planck area is another question -- although this has to be consideredat some point I agree.I have been doing that in http://qedcorp.com/APS/EmergentGravity.docNote Planck Area = Witten's alpha' (h = c = 1 convention) = 1/(String Tension)gravity becausespacetime is infinitely rigid but unstable.End of story. It's an approximate statement or a correspondenceprinciple.Z: Exactly. And that is *all* the so-called EEP is.But that is not Einstein equivalence -- unless you add an additional layer ofphysical interpretation.Einstein was not thinking about Lp^2 = hG/c^3 in 1915, although I thinkhis thinguntil 1925!Z: Immaterial to my general argument.Which is historical and not important in solving real problems of the day IMHO.Z: As far as I can see Einstein was simply (although understandably)confused aboutthe distinctions between empirical correspondence, formalcorrespondence, formalanalogy, and the literal identity of inertial and gravitationalphenomena.Quite possibly, but so what? It's no big deal today unless you can useyour new insightZ: Not new.to explain why cosmological constant is small, and the true nature ofboth dark energy anddark matter and also the string structure of lepto-quarks and gaugeforce bosons etc.Z: I'll leave the details to you.God is in the details. In this caseVacuum Coherence = Mind of GodZ: Remember, I don't claim to be a physicist.As a minor historical point maybe you are correct.Z: I think I am correct, but it is a major historico-critical point that has been thesubject of much controversy over the years.The issue is in fact taken quite seriously and I believe it has profound implicationsfor future gravitational physics.I am concerned now with Physics Today.I don't know withoutstudying theclassic writings more deeply.Z: As I said, it turns out that there is in fact no such thing as general relativity.As far as I can see this approach is a hangover from the fundamentallywrong-headed logical empiricism of the 1920s.How is the MTW argument regarding localized vacuum stress-energy basedon theEEP any different from arguing that since the speed of an objectcannot be measuredat an instant, the speed of the object has no physical meaning at aninstant?Hence, as Zeno might argue, motion is impossible, since at eachinstant the objectcannot be said to be moving?We enlightened moderns have the differential calculus. We are supposedto knowbetter.Eddington poin out in 1922 that there is no rational foundation forinsistence on sucha sweeping universal assumption (Einstein equivalence) -- that it ismerely a conjecturethat is subject to empirical test and that it is a mistake to assumethat the hypothesis*must* be true.And whether it is or is not is as far as *formal-empirical* GR isconcerned a purelyempirical matter.In other words, it was merely Einstein's guess. A sweepingextrapolation. A boldhypothesis.Based on what we know now, as a general law of nature, quite possiblya huge REDHERRING.This was later reitera by Feynman in his Lectures on Gravitation,where he actuallymade some gentle fun of Einstein (or at least Einstein's morefanatical followers).Clearly, we know there is a formal-empirical *analogy* betweengravitational and inertialfields, but only a partial one (Eddington 1922). But a partial analogy-- short of identification-- is a perfectly adequate basis for a weaker physical interpretationof the so-called EEP astechnically formula by Wheeler et al. that does not imply theidentity of gravitationaland inertial phenomena.That's only an idealization.The EEP is an idealization. But the EEP does not capture Einsteinequivalence withoutan additional layer of interpretation.IMO EEP amounts to an *ad hoc* stratagem whereby, in order to appearto save the Einsteinequivalence hobbyhorse, the fundamental distinction betweenequivalence as identity, andequivalence as mere local correspondence with flat-spacetime SR, issystematicallyobfusca, and a minimal agnostic epsilon-delta type technicalformulation is misleadinglyrepresen as somehow capturing the content of Einstein's principle(hence the misnomerEEP).It doesn't. It is *consistent* with it, but it does not capture thefull content of Einstein equivalence.That is why I call the MTW development of canonical GR a shell game.You have to keepyour eyes on that pea.What they do in Gravitation in certain important contexts is totacitly attach the additional layerof Einsteinian interpretation in their supposed proof of thenon-locality of vacuum stress-energy.The physical field is supposed to be elimina (i.e. annihila)at a point in a free-fall frame.But that is Einstein equivalence, and not merely EEP.If Einstein equivalence is empirically false, then it can hardly beinvoked as the theoretic basis forthe official interpretation of the GR formalism, of the EEP, or asthe basis for an argumentagainst localized vacuum stress-energy, as MTW would have it.However, under a suitable reinterpretation, the entiregeneral-covariant formal machinery ofcanonical GR still works fine. But at the same time, the reinterpretheory may point in verydifferent directions as regards development of deeper quantum theoriesof gravitation and thecorrespondence relation between the two theories.That this very bold Einstein concept of gravitational-inertialequivalence historically led Einstein tothe GR tensor field equations in the manner of a *heuristic guide*, orthat Einstein himselfmay never have explicitly abandoned his bold hypothesis, are neitherhere nor there as far as thecontemporary objective critical discussion of the subject isconcerned. IMHO.However, this was all poin out by Eddington and von Laue in theearly 1920s.Too bad M, T, and W apparently ignored them.Tidal differences in the g-force between P and P + dP meanscurvaturei.e. real gravity as opposed to simula gravity.Yes, exactly. That is what is meant by a permanent or intrinsicgravitational field.Fine, so what's the problem?The problem is the GR definition of vacuum stress-energy, the questionof its covariantformal representation, and the question of its localizability -- as Ithink you know.Again your point here is only interesting if you say there should bemore terms inGuv + /zpfguv = -alpha'Tuvalpha' = Ed Witten's inverse string tension (h = c = 1 convention).i.e. if you say there is some kind of power series in alpha'^n with nfactors of Guv?Z: That would require a specific underlying model, which I am not specifying.That's your job.The power series so far is not needed.Z: I am proposing a correspondence template for a more fundamental theoryfrom which phenomenological gravitation, as you say, emerges.I am arguing that there is no rational objection to conceiving of gravitation asa local physical disturbance of the physical vacuum that *causes* the motionof bodies to deviate from their normal geodetic paths.geodesics.EM force pulls them off timelike geodesic in 4D if they carry electric charge.Z Such a disturbance would propagate physically through the new aether,conceived as a non-material (or proto-material) medium of physical propagation.Old Hat. So what?Z: In other words, HYPOTHESES FINGO. I am throwing out all the old pseudo-positivistic taboos that have cast such a hideous spell over theoretical physics for wellover a century, if not longer.This influence is not propaga through a void, but through a physical mediumthat lies in the twilight zone somewhere between a material space-filling substance anda literal void.You seem to have forgotten about QED vacuum polarization plasma of virtual electron-positron pairs and virtual photons.Z: I strongly believe this was Maxwell's inchoate view, for which he was lampooned by therelativists.100 + years out of date.Z: In a deeper theory, under this basic model, the physical process through which gravitationmanifests itself will be shown to be closely analogous to the physical process throughwhich the phenomenon of inertia manifests itself. This *limi physical analogy* -- andnot curved spacetime and gravitational-inertial equivalence -- will then fundamentallyexplain the so-called EEP together with gravitational attraction and mechanical inertia.I have done this all already inhttp://qedcorp.com/APS/EmergentGravity.docZ: If the EEP can be rela on a formal-empirical level to a gauge symmetry of someunderlying quantum field, fine. That is all quite consistent with the abstract templateI am proposing.Then you have something interesting. Otherwise your point is trivialZ: The immediate corollary of this would be that Einstein's general relativity thesis was trivial.As I said, pull the other one.becauseLOCAL CLASSICAL GEOMETRIC VACUUM STRESS-ENERGY DENSITY TENSOR =alpha'^-1Guv = Tuv(Geometry)Z: Is this in linearized weak-field GR? Or are you talking about the exact solutions?The latter! This is strong field non-perturbative. I am talking the MACRO-QUANTUM local field equation.LOCAL MICRO-QUANTUM RANDOM ZERO POINT VACUUM STRESS-ENERGY DENSITYTENSOR = alpha'^-1/zpfguvZ: The effect of t_uv (vac) in the weak-field model on the non-linear corrections to the vacuum stressenergy density is obviously closely bound up with the non-linear character of the field equations.You missed my point here.Z: A deeper model would be expec to unpack this -- e.g. the non-Abelian character of the spin-1fields in the Deser-Feynman approach, which physically explains the self-gravitating nature of theEinstein g-field at a deeper level as another indelible characteristic of the permanent gravitational field.Is that the kind of thing you are getting at here?NO! If you read http://qedcorp.corp/APS/EmergentGravity.doc you would not ask that.Therefore Einstein's local geometrodynamic field equation is:Sum off all local stress-energy density tensors from classical geometry+ random virtual zero point quantum fluctuations + matter + coherentvirtual near field + radiation = 0Z: But what, in your model, is the *physical origin* of the local stress-energy density tensors fromclassical geometry?Read my paper. Eq. (I.5) is the answer.Z: Not curved spacetime, surely.Exotic vacuum /zpf =/= 0 is coupled to guv. The former is from modulating the Higgs intensity ofthe vacuum coherence, the latter is from modulating the Goldstone phase of the vacuum coherence.When no torsion and no hyperspace violations of metricity then we havea simple situation from the Bianchi identities that the 4-covariantdivergence of the classical geometry stress-energy density currentslocally vanish if the vacuum is NOT exotic, but NOT OTHERWISE!Z: OK, this looks interesting.You bet it is.Z: Again, you are reverting to your straw man here according to which Iam supposed tobe finding a technical problem with Wheeler's minimal agnostictechnical statement of the so-called EEP.I'm not -- except that it is only valid at a spacetime point.As every School Boy knows I suppose -- at least at Cal Tech.Z: Because they are reminded of this every school day by Dick Feynman -- orDick Feynman's ghost...Walks the parapets when the Night Wind Howls.Z: But if you want to glimpse part of what I'm getting at, just exchangethe epsilon and thedelta in Wheeler's formulation of EEP. For any given finiteneighborhood of aspacetime point, we can in (GR) principle always construct agravitometer that is sufficientlysmall and sensitive to detect the effects of non-vanishing Riemanncurvature around thatpoint, regardless of the state of motion of the object.All inside Einstein's famous elevator.This turns EEP' on its head.You lost me.Z: I guess so.No I was just getting tired of reading and my eyes glazed over. I was likeAlcibiades with Socrates after a night of heavy drinking and ofawzing.Yes, I understand what you are saying. I have said it myself, but your attitude about it is odd.This is simply a matter of bandwidth/resolving power of the curvature meter untilone reaches the Planck area. The larger the bandwidth the smaller the size of theLIF. The key number is (L/r)^2 where L is size of LIF and r is scale of localcurvature. Approach to singularity is r --> 0 so you cannot obeyEEP which requires (L/r)^2 L << 1. This is elementary my dear Z.Z: It turns out (and I didn't know this when I first got onto it) thatthe position Iam advancing here is essentially Eddington's as set out in 1924. Atthat time heviewed Einstein equivalence as heuristic and tentative in character,and not asa fundamental principle.I say he was right on the money.This is the view that was later echoed by Bergmann, Synge, andothers.EEP as technically formula by Wheeler is fine -- but it isconsistent with eitherinterpretation (Einstein's or Eddington's).So it seems your point is one of the history of relativity on howEinstein's ideas evolved.Z: You don't seem to see that this entails a profound shift in thephysical meaning ofthe GR field equations, and that this means that *we do not haveactual generalrelativity*, regardless of the impressive empirical accuracy ofstandard GR.You lost me again.Z: The empirical accuracy of GR is neutral with respect to the re-interpretationof the EEP that I am proposing.If we do not have actual general relativity, then we have not in fact*explained* theequality of gravitational and inertial mass, as Einstein thought hehad. We havesimply *assumed* it.Again you are too subtle for me here.Z: Then so is Einstein, Jack.This is *his* reasoning.There is no question about this. I have all the quotes and citations.The crux here is simply thatlight rays move on null geodesics, and nothing moves on spacelikegeodesicsin torsion-free space-time.Z: The crux here is, what, physically speaking, is a geodesic?The straightest path in a curved spacetime that obeys the geodesic equation forIt is the longest proper time for a bundle of neighboring world lines withsame starting and end points in sense of Calculus of Variations.Z: *Why* do material objects and light rays move in straight lines? *Why* dothey deviate from these straight geodetic paths under certain conditions?Why?Scientifically meaningless. It's the Ansatz of the Action Principle.Physics is not asking why it is asking how.That is, if there is in physical reality no such thing as curved spacetime, exceptin the sense of an abstract mathematical model?This is precisely the problem as Feynman presen it.'Cite Feynman here. Look you can say this about any theory of physics.This is not interesting. This is Wigner's The unreasonable effectivenessof mathematics in physics. is metaphysics not physics.You cannot have light, you cannot have anything move on a timelikenon-geodesicnull geodesicsphysically if there were no electric charges. This already shows thatgravity must emegefrom electromagnetism. No charges no weight!Z: I suspect this is a fallacy. Let me think about it.It is not a fallacy. You cannot have light without electric charges. Indeed, in Wheelerand Feynman they only have electric charges NO LIGHT! Without lightno light cones as rocklike IT geometrodynamic realities as distinct from thoughtlike BIT formal possibilities.Therefore, electricity is more fundamental than gravity. This is whyelectricity is micro-quantum renormalizable and gravity ain't. This was Sakharov's keyidea I bet! Gravity is an emergent MACRO-QUANTUM collective propertyof the unstable micro-quantum electrodynamical vacuum.The Question is: What is The Question?Z: The term general relativity, like EEP, is thus in that case amisnomer. In the MTW development of GR it amounts to an elaboratebait-and-switch routine.It also opens up a prospect for the resurrection of a suitably refinedneo-Lorentzianconcept of a non-material aether (physical yet non-material mediumof propagationacross the vacuum) to be sharply distinguished from spacetime as avoid. Under thismodel, it is the *physical disturbance* of this aether by thepresence of matter thatcauses deviations from straight-line motion.Less words more math would help clarity here.Z: The words are carefully chosen, and every word I use here means something.Math is objective. Meaning here is too subjective.Z: If we don't actually have *general* relativity, then we don't haverelativity, period -- sincethat implies and demands the physical relativity of *all* motion (A.Einstein).Relativity is the stillness in the motion, i.e. invariants of groups transformations.That's all it is. There are different groups like the 15 parameter ConformalGroup for spacetime structure broken down to 10-parameter Poincare Groupto get invariant rest mass from dark matter /zpf < 0 exotic vacuum coresi.e. Brian Greene's vibrating strings of energy. Brian should have saidvibrating strings of negative micro-quantum zero point energy densitywith positive pressure with vibrations in the extra space dimensions.Z: No Einstein equivalence, no general relativity. This *according toEinstein's ownclassic arguments*.This is more a legal argument then a physics argument.Z: Natural osophy -- which I believe is about to make a major comeback.Once the dead hand of pseudo-positivism is finally lif.Hawking proudly declares he is a positivist BTW.Z: This is IMO profoundly iconoclastic and could have deep implicationsfor the furtherdevelopment of gravitational theory. But the logic is inescapable IMO.Depends what you mean by logic.Z: At least I know what I mean.How do I know you know? Note I said How not Why.Is renormalization theory forZ: Good question.Logic never stopped great physics discoveries before and why should itnow?Look at Niels Bohr as a good example.Z: Of course logic can be misapplied. That doesn't mean it should simply beignored. Syntax and semantics must always work hand-in-hand.Logic is like geometry - many different kinds, e.g. quantum logic is not classical logic.I do not see however how this will lead to new physics today unlessyoumean thataddition torsion local gauge field and possibly local gauge fieldsfromALL of theconformal group will modify EEP which is only based upon the4-parametertranslation group of the 15 parameter Conformal Group for Minkowskispace-time.Z: I am not trying to modify EEP. I am simply proposing an alternativeinterpretation to thosebased on Einstein equivalence.The alternative interpretation points to a very differentcorrespondence model betweenstandard GR and a deeper theory of gravitation. It may hold someimportant clues to howthe analogical relationship between physical gravitation andmechanical inertia, and the basisfor weak equivalence (strict proportionality of gravitational andinertial mass) will beexplained in the deeper theory -- which will presumably be some kindof quantum fieldtheory of the gravitational vacuum.I don't see how without specific toy models of gedankenexperimentsand/or mathematics.Also I have already explicitly solved all this with equations!Electricity is more fundamental than gravity.Quantum electricity is micro-quantum unstable. Gravity emerges out ofthis instability (inflation in large scale) along with exoticvacuum dark energy/matter as emergent MACRO-QUANTUMmore stable smooth curved spacetime maybe with torsion.That is the more fundamental theory! It gives Einstein's equations!Gravity is like the Meissner effect - a MACRO-QUANTUM effect.It's not that there is no general relativity, there is NO CLASSICAL PHYSICS!Its ALL MACRO-QUANTUM PHYSICS.Z: You should take my arguments seriously, Jack, even without the math. I reallythink my proposals could help you with your program in the longer term.I see no evidence for that. Your proposal is like asking a caterpillar to think how it walks.I have all the essential empirical mysteries accoun for in a semi-quantitative algebraic fashionfree from any kind of passion at a distance.I refer to the paper by Utiyama I think in mid-60's also Kibble'slaterpaper inwhich the general relativity principle is rederived as a kind of localYang Millsgauge principle in the curved space-time base space of the fiberbundlewhere thefiber is the U(1)SU(2)SU(3) or its GUT internal symmetrygeneralization. Roughly, the gauge forces arein the principle bundle with unstable globally flat space-time as acoset space mod the internal symmetrysubgroup of the total group and the lepto-quarks are the associavector bundle. One thendoes the same trick again inside the coset space whose symmetry groupis the Conformal Group.Fine. This was also Feynman's approach. He also alluded to gaugesymmetries asthe basis for EEP *by way of formal correspondence* with standard GR.Yes, that is how everyone in theoretical physics today thinks about it.Z: OK. This does not require Einstein equivalence.WRONG! Einstein's equivalence is simply a consequence of locally gauging the 4 (energy-momentum) generatorsof the translation subgroup of the 15-parameter Conformal Group.This gives the locally flat tangent bundle of GR and you can locally gauge using tetrads which is the formal contentof EEP! This local gauge compensating field that replaces the global translation group with the local Diff(4) group is the distortion field of the worldcrystal lattice where in the infrared limit >> Planck area, curvature = disclination topological string defect density and torsion = dislocation topologicalstring defect density (see Hagen Kleinert's math here).That is EEP is simply an almost trivial application of the Local Gauge Principle to a very simple group -- thetranslation group.Z: So why does Steve Weinberg -- who knows something about QFT -- call himself aheretic when he discusses such matters in Gravitation and Cosmology?Does this gauge symmetry of the underlying Yang-Mills field imply thatgravitational andinertial fields are, physically speaking, literally one and the samephenomenon?I do not understand your question unless you give the math.Z: This is not a mathematical question. The math is neutral to the question.I do not understand what you mean by an inertial field?I mean by inertial field the symmetric torsion-free Levi-Civita parallel transport connection field = inertial field forThe g-force is the inertial force.In the LIF the g-force is made to be zero to a good approximation for all Earth and NASA near space physics.This means that locally the tensor + non tensor part of the connection cancel each other.The tidal curvature differential is still there, but small in Earth and near space physics.Connection = Tensor + non-TensorZ: OK.Real gravity is from tidal gradients of Tensor part of ConnectionZ: Permanent gravitational fields are mathematically described by the tensorcomponent of the connection field.So where's the beef? I see no there there.Connection = 0 in any LIF.Z: *Net combined gravitational-inertial* connection = 0 at some point in any LIF.g-FORCE = ConnectionZ: But Jack, mathematically speaking, we get a non-vanishing connection fieldeven in a purely classical 2- or 3-space in *any* non-linear coordinate system.Formally yes. But that formalism will not describe a real physical situation unlessother conditions are met like a Tuv source for example.Given any atlas of overlapping local coordinate patches one must computeGuv from them. If there is no suitable Tuv there that obeysGuv(Geometry) = -(String Tension)^-1 Tuv(Source Stress-Energy Density)OrMarble Geometry LOCAL Stress-Energy Density + Wood Source LOCAL Stress-Energy Density = 0that atlas in not physically realized nor is any Diff(4) equivalent bundle of local gauge transformations of it.Remember this is manifold theory with overlapping patches sewn together by Diff(4) transformations at fixedevents P. Part of your problem is that you think globally not locally. Euclid's plane geometry and globalCartesian geometry breakdown in the micro-quantum --> MACRO QUANTUM vacuum instabilityphase transition in which total phase space volume collapses to allow emergence of new ordersetting the direction of the irreversible arrow of time in the early post-inflationary universe.Z: We get metric distortions in purely classical (i.e. Newtonian) accelera frames,and not just under Lorentz transformations in Minkowski space.That doesn't necessarily mean there is a *physical effect*.So this is about *physical interpretation* of the math. The math is the same orat least very similar in either case. Just because you have a *mathematical* connection field doesn't mean you havea *physical field*. You may have a *purely* kinematical field. Sorry if I'm re-stating the painfully obvious.You are not asking the right question.Given any atlas you compute Tuv and then look to see if that Tuv is there.If it's not then that atlas is not physically realized.I mean an equivalence class of atlases mod Diff(4) for zero torsion case.I also mean a Diff(4) equivalence class of Tuv representations of the same actual source distribution./zpfguv also acts like the Tuv source if there is also exotic vacuumrandom virtual zero point dark energy/matter.Note that MHD fields in say pulsars are MACRO-QUANTUM coherentnonrandom states of virtual photons not same as the random zero pointvirtual quanta of the exotic vacuum phases of anti-gravitating dark energyand gravitating dark matter.If your atlas has a curvature tensor field over the patches, it is not a kinematical field.If the corresponding Tuv is not there that atlas does notdescribe the actual curved spacetime region of interest.You have a space of solutions, or in this case a space ofatlases covering a manifold with a metric. Not every point in thatspace of atlases is the correct solution for that metricmanifold.In LIFTensor g-force + non-Tensor g-force = 0Z:P OK.So that's compensation at g-force level.Z: OK -- if it is interpre that way.That was not Einstein's interpretation.Sure it was! The painter falling off the ladder felt no weight.This was Einstein's motivation in his own words.Tidal force is the derivative of g-Force!i.e. f(P) = 0 but df(P)/dx^u =/= 0 in LIFZ: OK.If not, then such theories are inconsistent with Einstein equivalence-- although perhapsnot with the so-called EEP in its most agnostic formulation.You lost me.Z: I guess so.Any quantum field theory of gravitation -- or any other fundamental theory ofgravitation -- that entails locally measurable physical distinctions between theinertial and permanent gravitation fields is *inconsistent with Einsteinequivalence*. That should be completely clear at this point.First of all there is no local micro-quantum field theory of gravitation that isconsistent and useful because that is a category error asking an ill-posedquestion of Nature. No one claims a locally measurable physical distinctions between theinertial and permanent gravitation fields that is your Red Herring.You can ask. Is there a curvature tensor at P that does not vanish?Am I in an LIF at P or in a LNIF at P?The curvature tensor not vanishing is so in any local frame LIF or LNIF.Those are the only meaningful questions.You got any others? Apart from issues of torsion and exotic micro-quantum zero point vacuum effects?Random /zpf is to smooth guv as normal fluid is to superfluid./zpf = 0 gravitationally neutral non-exotic vacuum is 100% superfluid.Omega(/zpf = 0) seems to be not bigger than 0.05 where total Omega = 1.wasEinstein's. It isinconsistent with Eddington's as sta in Mathematical Theory ofRelativity.MTW seem to use both, which strikes me as an example of Bohriancomplementarity-- AKA speaking with forked tongue -- in the context of spacetimephysics.That is a very bold hypothesis, as Feynman poin out on manyoccasions.But it is at the core of Einstein's concept of generalrelativity,as Einsteinhimself consistently emphasized (specifically to von Laue).Of course, this was later formula as a local cancellation of thegravitationalforce field in a free-fall frame, together with our ability torendertidal effectsnegligible by going to a sufficiently small neighborhood. Thismakesit lookon the surface like the Einstein principle is still valid -- hencethemisleadingacronym EEP.Forget what Einstein allegedly thought in his early days.Jack, this was integral and indispensable to Einstein's idea ofgeneral relativity.So, if you forget about this -- and also Pauli's entire 1921exposition of GR --you then have general relativity *without actual generalrelativity*, as I said earlyon.I mean, this is a historical point about the initial immatureconception of relativity that gotfurther refined into the modern ideas launched in MTW.Z: No, it means that there is in fact no such thing as generalrelativity. That isa very profound shift of interpretation IMO.All we really have now is *general covariance* and a tensorrepresentation of thegravitational field, and EEP for empirical correspondence with SR.That's good enough.Z: OK. So you actually seem to agree with me.That was not obvious a year or so ago.Even Einstein eventually admit that general covariance in and ofitself is emptyof physical content (see Autobiographical Notes).Common knowledge.Z: But the implications of this in conjunction with certain other observationsare most definitely not common knowledge. To the contrary, they are considered to be heresy.Examples?Looks like I was right.But if you are willing to drop this and hew to a consistentnon-Einsteinian interpretationof EEP, then fine.But then, the MTW argument against localized vacuum gravitationalstress-energyfalls apart (though of course that does not in itself mean there areno other valid objections).The only way you can attack MTE there is to say that their initialassumption that the localizedvacuum tensor is quadratic in the connection is a Straw Man, i.e. notcomplete.Z: Here you are ignoring, or not understanding, my proposal for acanonical localdecomposition of the connection field, which I contend avoids allthese difficultieseven within the existing GR formalism with its unified abstract metric.like I did above.it goes.You don't seem to remember, but I gave you as much as this more than a yearago in an e-mailYou are right I do not remember that.That there isanother form based only on the nonlinear products of the curvaturetensor but that wouldchange the field equation from (neglecting zero point /zpfguv)Guv = -(8piG/c^4)TuvtoGuv + Nonlinear products of 4th rank curvature tensor = -(8piG/c^4)TuvThe extra terms are a power series in Lp^2 = hG/c^3they may be there, but are too small on the macro-scale.Is that what you mean?Z: I don't think so. I am talking about a local decomposition of thestandard Christoffelconnection.Like I showed above - standard stuff. So what?Z: So what? So what?THERE IS NO SUCH THING AS GENERAL RELATIVITY.I cannot understand really what you mean until I see formal statementsin math that pin down the ambiguities of ordinary language.OK. Of course this has to be done.I think I did it above. This should not take years to do.Z: That much I did years ago. The mathematical development goes further than that.Your point is elusive and ineffable. You seem to be stuck on some early informal remarks that Einstein may have made as scaffolding. Now hisstatue is complete, the Ceiling of the Sistine Chapel is there with the scaffolding removed. You have confused the temporary scaffold with thepermanent work of art!Z: I gave you a formal expression some time ago but you apparentlyignored it.I forgot it.Z: I guess.I recrea it above.Z: See above.This is principally a matter of proper interpretation of the metricgradients -- even inthe abstract context of pure differential geometry.which breaks down when scale ~ Lp* and which emerges from local giantvacuum coherent wave.Z: On the physical level, it is tied to a close analysis of exactly whatit means to mathematicallymeld physical time into a Riemannian spacetime manifold, and preciselyhow to properlyinterpret the local transformational properties of the connectionfield on a curved (i.e.deformed) Riemannian manifoldYou lost me without the math.That *is* math. You mean with out the symbolic expression?I could call the Riemannian manifold M and the the coordinate transformationsT and the stretchless deformation (of M) D if it helps.ThenT(M) --> g_uv, w | IandD(M) --> g_uv, w | Gandg_uv, w| Einstein = g_uv, w | I + g_uv, w | Gand then, locally,Is that what you mean?I don't know. Your notation is not immediately obvious to me.I would writeguv(locally curved) = nuv(globally flat) + (world crystal strain tensor)uvDiff(4) is then local Goldstone phase transformations.This is NOT perturbative linear approximation, this is non-perturbativeThe coupling strength of second term on RHS is alpha' = (string tension)^-1infinite string tension means NO GRAVITY.Z: Einstein may simply have gone wrong there -- a victim of his ownwishful thinking --regardless of his impressive heuristic success in arriving at the GRfield equations.I crave heuristic success!Music from Gounod's Fausthttp://www.classicalarchives.com/m/023/act_1_du.midAs you should, since you are working in the context of discovery.Z.ZThis is why I feel uneasy about Bohr's reliance on ordinary languageinthe quantum reality problem.This is a complex issue that I don't really have the time to get intohere. But I do agree thatBohr's insistence on the irreducible use of ordinary language andcommon sense conceptsin describing the results of experiments is very dubious. At the sametime I don't think thismeans that the only satisfactory language for discussion and analysisof the problems ofQM is formal mathematics. I would say that this approach simply avoidsthe entire problemof the proper interpretation of the QM formalism.I believe this was Bohm's view.Which is what I originally argued: the bare EEP does not establishthat thegravitational energy density must vanish at a point, or that itscomponents dependupon the frame of reference in a non-covariant manner. It onlyrequires that thenet measurable combined gravitational and inertial forces vanish at apoint in somecoordinate system.To get the true gravitational stress-energy, we simply ignore theinertial contribution-- that's all.Eddington himself explicitly states that in GR the inertial field hasa stress-energythat is frame-dependent and represen by a non-tensor. But this isa*fictitious*stress-energy, unless you believe in Einstein equivalence *asoriginally sta* --which it now appears that you don't.He wasperhaps a bit confused whilst the theory was immature.The point is that it's coherent conceptually today in the form MTWhave.I cannot agree. See above. This is a *real interpretive dichotomy* atthe most fundamentallevel.Now you could say somethinglike this about Schroedinger, who reallythought he had awave theory in the classical sense -- but later had to give this upfor a number of reasons.Einstein never explicitly abandoned equivalence and true generalrelativity. Not even inhis Autobiographical Notes, which is just about his last word onthesubject.You cannot render tidal effects negligible in the approach to asingularity until effective Planck scale is reached.That scale may not be 10^19 Gev after all. It may be 1 Gev?That may well be the case, but this is not part of canonical GR. Nodoubt a deepertheory, if it ever finally comes, will answer such questions.Ed Witten thinks that's M-theory. It's now on NOVA! I am beginning toread Witten. I am getting a little uneasyabout all this duality stuff in string theory because it is beginningto remind me of mydebate with Hal Puthoff on his use of isotropic r vs. curvature rin the SSS model.This debate is described in my Dec 2002 book Space-Time and BeyondII.M-theory may be the final proof of the bankruptcy and heuristicexhaustion of theformal-empirical methods of modern physics. On the other hand, underthe rightinterpretation, it might open up new vistas. We'll see.No argument from me on that one! What a double standard eh? -- abouthype in science I mean.People are always telling me to connect my theories with experimentsand observations. Wellthat's what I have done more so that anything on NOVA's ElegantUniverse although I doconnect my math with their stringy alpha' and indeed I think what Ihave done inhttp://qedcorp.com/APS/EmergentGravity.pdf is good for Witten & Co Ihave connec theirvaporware more closely to observations of important stuff like thecosmological constant.But the extravagant resort to these multi-dimensional hyperspaceslooks verysuspicious to me -- regardless of how neatly the Standard Model fitsinto theformalism.Pythagorism run amuck?My debate with Puthoff was that he was misinterpreting the physics notrealizingthat the expansion of space inside a critical radius was an illusionofnot realizingwhat the coordinate patch was in the curved differential manifold.OK.MattVissermakes this clear in Lorentzian Wormholes in contest of Kruskalcoordinates.There is a kind of duality there withr' = r*^2/rbut r' and r are both OUTSIDE the horizon. Puthoff and Ibison makethe conceptual error that r' is INSIDE the horizon!Couldn't this simply be the result of a mathematical ambiguity?No, good books like Matt Visser's Lorentzian Wormholes are good onthis.I don't think Puthoff and Ibison ever really read that book or ponderedits meaningif they did.In any case, Puthoff is not claiming that his PV theory is any kind offundamentaltheory of gravitation -- just a highly computable working model thatmight beat least pragmatically justified by some future deeper theory.Not so, I think he claims he has a viable alternative to Einstein.I honestly don't understand why you think you are in directcompetition with Hal.Because he got all the money people in the fringe BPP people to thinkhe is on theright path - not that there is a lot of money there. But because of hispast top securityclearances he has influence and access inside USG Black Ops and in factthere is afactional fight inside USG right now about all this - more than that Icannot say. So theissue is one of whistle blowing on wasting tax payer money on thingsthat have nochance of working whilst ignoring things that do.I am wondering if Witten, Greene & Co are making a similar conceptualerror in that really they ignore the physics INSIDELp*^2 which G.E. Volovik in Universe in a Helium Drop says isessential for solving the smallness of the CosmologicalConstant problem. It's like in condensed matter physics not goinginside the unit cell of the crystal lattice. If you do that youwill get a zero point energy for phonons that is much too large! Thisis Volovik's insight.String theory is like 2D field theory because the string sweeps out aworld sheet in ordinary space-time rather than the 1D world line. Thisis a great thing because it essentially does away with the infinitiesCosmological Constant problem, which worries Witten and rightly so.problems.NO! String theory give bad prediction /zpg = 10^66 cm^-2 whenexperiment says/zpf = 10^-56 cm^-2 because Witten's strings are only 10^-33 cm asBrian Greenerepeats many times in the NOVA vaporware.String theory is no better than local field theory on this issue!Witten understands that!They lack my giant vacuum coherent field!http://qedcorp.com/APS/EmergentGravity.docAfter all - you get an infinite mass density and infinite electricalforces insidegravitationalforce is infinite at zero separation of two mass points.The classical electron was a hopeless conundrum even in Lorentz'stheory.THIS IS NOT THE PROBLEM.There are analogies of string theory with lattice spin Ising modelswhich have a duality relating a T theory to a 1/T theory in a duallattice.Witten introduces the famous alpha' as basically a new stringfundamental constant. He does not seem to connect it to the Salamgravity I worked on in 1973.Yet more knobs and dials.Is any of this really physics? Can this kind of theory really be saidto predictanything? Other than in the *ad hoc* formal manner of abstractmathematicaldescription?I'll see if I can comment on the stuff below after I have looked atWitten.Using his h = c = 1 units. Witten's alpha' is essentially aneffectivefield Planck area. If we believe Susskind's world hologram we havealpha' = Lp*^2 = Lp^4/3L^1/3at scale LIf we choose L = c/Ho in a kind of Mach Principle of large scaleinfluence on small scaleHo = HubbleLp* ~ 1 fermiThe problem with this is the time dependence in H(t) where Ho is thepresent epoch value.Note, in Witten's conventions, energy is 1/LengthThereforealpha' is the universal Regge slope, which for hadronic resonance hasalpha' ~ (1 fermi)^2Quantized spin of resonance = alpha'(Energy of resonant peak)^2 +interceptalpha' is reciprocal string tension since Energy/Length ~ 1/Area intheh = c = 1 convention used by Witten & Co.In my theory/zpf = (alpha')^-1[(alpha')3/2|Vacuum Coherence|^2 - 1}Einstein's gravity emerges fromguv = (Minkowski)uv + (alpha'){Goldstone Phase of VacuumCoherence)(,u,v)}So this seems to map directly over to some bi-metric version of GR.No I do not see that at all. The SUM on RHS is not bimetric anymore than2 = 1 + 1 is in reality a pair of two 1's with independent parallelexistences.Youhave a flat Minkowski background with a Lorentz metric, with inertialfieldsconceived as artifacts of non-linear spacetime coordinatetransformations,PLUS a *physical metric* describing gravitational phenomena that isdirectlyrela to your BEC Goldstone phase.Am I right?Yes, but it is only the sum that is physical. I do not see twocoexisting independent metrics apart fromlocally flat tangent bundle idea of standard GR with tetrad map betweenLIF geodesic fiber and non-geodesic LNIF base local framesIf so, then this is NOT Einstein's gravity. It is *Eddington's*gravity.This was also Feynman's general approach in his Lectures onGravitation.It is BOTH! I haveGuv + /zpfguv = alpha'TuvAs I said, I think your task is going to be a lot easier, as far ascorrespondencewith GR is concerned, under my proposed alternative interpretation ofthe EEP.You cannot simply sweep all these problems under the carpetemergence IMO.anholonomic torsion field potential = (alpha'){Goldstone Phase ofVacuum Coherence)[,u,v]The O(2) internal symmetry of this complex numbered scalar VacuumCoherence local field implies 1D string topological defects in 4Dspacetime asa rigorous theorem in the text books.OK.More generalized models of O(N) hypercomplex numbered MACRO-QUANTUMVACUUM More is different (P.W. Anderson) coherence order parameterswill give the brane world topological defect generalizations ofthesestrings that should also have torsion on the microscale.OK.The most from the least.BTW, how does your theory explain mechanical inertia?Exactly as in Wheeler's book Geometrodynamics with Mass withoutmass except now I have G* = 10^40 G(Newton) at the fermi scale.OK. I'll have a look.I star working on Wheeler's book Geometrodynamics in 1966. Wheelerspoke at UCSD frequentlythen.The characteristic rest mass of the spatially extended lepto quark ofCharge without charge rotating with Spin without spin ism = e^2/zpf^1/2 = e^2/Lp* = e^2(alpha')^-1/2because Vacuum Coherence -> inside the Type II superconductorquantized flux vortex vibrating string exotic vacuum dark mattercore with ends pinned to the 3Dim brane world we are stuck on like EdAbbott's Flatlanders if the basic Witten & Co ideas are on righttrack.So in your theory, inertial effects result from the physicalinteraction of matter,conceived as branes, with the quantum vacuum, conceived as a virtualBEC?BRANES emerge FROM virtual BEC.strings emerge from virtual O(2) BEC which is only low energylong-range limiting case of shorter-scale O(N) BEC in some kind ofO(N') or G(Mystery) group hypercomplex number generalization ofEinstein's real space-time continuum.Say bye bye to Mach's principle.Not ifLp*^2 = Lp^4/3(c/Ho)^2/3which has a problem however.These 1 Dim strings vibrate in the extra boson space dimensions andtheextra fermion supersymmetry matrix space-dimensions forming theCalabi-Yau space generalization of the Kaluza-Klein hyperspace of the1920's.OK.But it only takes one physical effect that is not locallynegligiblein this senseto blow out Einstein equivalence.Einstein equivalence is only a classical weak field approximation oryour correspondence principle in the informal sense for the zerotorsion limit.I'm not sure exactly what you mean here. Einstein thought it heldwithoutrestriction.Looks like you don't agree.I am not sure without doing a careful look. In any case, of coursethere have beensubtle modifications or refinements of Einstein's early thinking.Theseare smallcorrections so to speak. Only minor clarifications of his greatinsights.This is simply not the case, Jack. What I am talking about is aprofound counter-revolutionary paradigmatic shift back to some kind of an aether,conceived as anon-material yet physical medium of propagation across the physicalvacuum.So it is precisely Einstein's original insight -- that bothgravitation and inertiacould be jointly reduced to a distortion of an abstract metric in anabsolute void,without reference to any physical medium of propagation -- that is inquestion here.Look, Einstein was a wonderful man and a creative genius, but businessis business.Music from 'The God Father plays in background.We need to move forward. Let's not be too sentimental about this.There isnothing revolutionary in the distinctions you propose here that I amable tounderstand at least.Then perhaps -- and I don't say this lightly -- you don't reallyunderstand Einstein.You don't seem to realize that you have in fact abandoned his theoryof generalrelativity.Quite rightly, IMO, since THERE IS NO GENERAL RELATIVITY.There you go again sounding like Brian Greene on NOVA! That is a lot more than a mere detail of history. That can hardly bedescribed as a slightadjustment or refinement to Einstein's original insight.You lost me. I am only a humble post-Quantum non-mechanic.It is in fact a wholesale *abandonment* of Einstein's originalinsight, which is nowdemo to the status of a mere heuristic tool -- mere scaffolding tobe discarded oncethe cathedral is built, in favor of more solid and durable buttressingthat is more inkeeping with the final architecture.I am not sure what happens when there is torsion-spincoupling. It can break down for a variety of reasons.Exactly -- you're not sure. The fact is it's anybody's guess and isultimatelyan empirical question.Not quite - there is a lot of work in the published literature - it'sonly my personal lack of knowledge here I allude to.I'm not sure we're on the same page here. But I *am* talking aboutspinningEinstein equivalence-- within the framework of canonical GR.space-time. It's complica butstandard in MTW et-al.If ALSO there is TORSION then additional coupling of spinning testAkimov in Moscow says that is a big effect with weapons applications.One guy here who came to ISSO 2000 also said that and he was working onareport. Most researcher pooh pooh that. I do not knowfirst-hand.Yet Einstein thought he was completely sure, and said so. That's whyFeynmanmade fun of him in Lectures on Gravitation.Z.Again this is very minor compared to what is happening now and what Iam talking about above in relation toWitten & Co.See above. It changes the entire meta-theoretic relationship betweenGR and thedeeper field theories of gravitation. It profoundly changes ourunderstanding of thevacuum and its relationship to gravitational and inertial phenomena.Show me how in detail.I do not have time to absorb all your points below. Later.OK.=== === Subject: : Need advice on letters of recommendation I am a senior and I will be needing to fill out applications for graduateschool. My problem is that I am on the quarter system and the quarter is aboutto end. We will not resume until the beginning of January. I'm pretty shy andhave not asked any of my professors for letters. I'm just not sure how to askthem and now that I basically have no time left, I was just wondering how Ishould go up to them and ask. I have had the same professors for a lot ofclasses in some cases but I'm not sure whether or not lower level classes wouldgive a professor enough to say anything about me. Is there any standard way togo about this? Most schools seem to want three and for me that is a lot.Thanks for any advice.=== === Subject: : Re: Need advice on letters of recommendation> I am a senior and I will be needing to fill out applications for> graduate school. My problem is that I am on the quarter system and> the quarter is about to end.> We will not resume until the beginning of January. I'm pretty shy> and have not asked any of my professors for letters. I'm just not sure> how to ask them and now that I basically have no time left, I was just> wondering how I should go up to them and ask. I have had the same> professors for a lot of classes in some cases but I'm not sure whether> or not lower level classes would give a professor enough to say> anything about me. Is there any standard way to go about this?> Most schools seem to want three and for me that is a lot.> Thanks for any advice.letters of recommendation are about the most ludicrous mechanism inplace in academia - it's a shame. institutional admissions exams wouldbe far superior.anyways, since letters are inevitable, you need to get them asap fromprofessors who you know will give only good/excellent reports andremarks. if possible, get the professors to issue them to you, thatway you do not have to bother them repealy, plus that will ensurethat all your materials arrive timely. full contact information andtitle should remove any doubt about legitimacy...=== === Subject: : Re: Need advice on letters of recommendation> letters of recommendation are about the most ludicrous mechanism in> place in academia - I don't know about most ludicrous, but there are some kinksin the system. We talk about how lazy and irresponsible studentsare, but the percentage of slacking professors is also a bithigh. My opinions about the writing of recommedations:1. When a student (or anyone) asks for a letter, it is implicit that they are asking Will you write me a _good_recommendation. And if you agree to write a recommendation,then you are implicitly agreeing to write a _good_ one.And by this I mean, you write a letter about whatever goodqualities the student might have, however few that mightbe. If that damns him with faint praise, one has at leastac with honor.2. The writer must write honestly and should do his homework. Actually look up the grades, and determine ifthe student really was in the top 5% of students or the best student I've ever had. Check out any factsfrom the resume that are referenced in the letter.3. The purpose of the letter is not to be just another transcriptor another academic exam score. Something else is wan here.Of course the student has passed classes and exams. Has thestudent changed since he entered college as a freshman?The graduate school is going to admit a pile of students, and several of them are going to drop out, taking their stipendswith them, which is not an effient use of their financial aid.They want to know if this student is a good risk of a TA-ship.This is the heart of the letter, I think. And everyone has toget at it in their own way. My style is that I try to thinkof at least one concrete anecdote that demonstrates the student's perserverence, longevity, stability and adulthood.(Which shows that I know first hand what I'm talking about.)Bart=== === Subject: : Re: Need advice on letters of recommendationThanks for the replies. I talked to one of my professors yesterday that I havethe most experience with. He sugges the other 2 professors that shouldwrite my recommendations. He told me not to ask one Professor that I hadpretty well with, so he must have known something I don't.=== === Subject: : Re: Need advice on letters of recommendation>letters of recommendation are about the most ludicrous mechanism in>place in academia - it's a shame. institutional admissions exams would>be far superior.It's doubtful that, even if examinations were superior, they'd be*far* superior. And saying something's true doesn't make it so.=== === Subject: : Re: Need advice on letters of recommendation>letters of recommendation are about the most ludicrous mechanism in>place in academia - it's a shame. institutional admissions exams would>be far superior.Letters of recommendation may well be ludicrous. I have no reasonto believe, and much reason to disbelieve, that institutional admissions exams would be any better at deciding who would bea good graduate student. Go into detail on how you'd make suchan exam, if you don't mind.I, by the way, am sorely lacking in the experience of administeringadmissions evaluations of any sort whatever (but I do have all toomuch experience at setting exams, hence my dubiety that they wouldbe any damned good for this purpose). While you're describing your proposed exam, you might just run over your own experience in administering admissions.Lee Rudolph=== === Subject: : Re: Need advice on letters of recommendation> letters of recommendation are about the most ludicrous mechanism in> place in academia - it's a shame. institutional admissions exams> would be far superior.> Letters of recommendation may well be ludicrous. I have no reason> to believe, and much reason to disbelieve, that institutional> admissions exams would be any better at deciding who would be> a good graduate student.perhaps you do not believe that a solid undergraduatepreparation is key component in graduate studies success.is that it?> Go into detail on how you'd make such an exam, if you don't mind.i do not need to go into any detail to ascertain that aresounding reason for the lack of institutional exams in theuni states is correla with the economic and logisticsrequired to put such systems in place.> I, by the way, am sorely lacking in the experience of administering> admissions evaluations of any sort whatever (but I do have all too> much experience at setting exams, hence my dubiety that they would> be any damned good for this purpose). While you're describing your > proposed exam, you might just run over your own experience in > administering admissions.>ps posting through mathforum.org bites=== === Subject: : Re: Need advice on letters of recommendation permission for an emailed response. The GNU project will probably not be Posix conformant, Tom said noncommittally> I, by the way, am sorely lacking in the experience of administering> admissions evaluations of any sort whatever (but I do have all too> much experience at setting exams, hence my dubiety that they would> be any damned good for this purpose). While you're describing your > proposed exam, you might just run over your own experience in > administering admissions.One year when I worked there I was an admissions reader for MIT. Weread undergraduate admissions. The system as it exis then was toocomplex to go into now, but the recommendations were in factimportant. One question MIT asked was how has this student dealtwith failure in the past, and the most illuminating answer I got fromthat was a teacher who said Johnny has never experienced significantfailure in his academic work--apparently thinking this was good.Thomas=== === Subject: : Re: Need advice on letters of recommendation>I am a senior and I will be needing to fill out applications for>graduate school. My problem is that I am on the quarter system and>the quarter is about to end. We will not resume until the beginning>of January. I'm pretty shy and have not asked any of my professors>for letters.Everyone else has given you fine ideas about letters. But I'd like topoint out something about this comment. It's OK to be shy, and many math majors are, but college and grad schoolare really good times to grow past this. We all know the jokes abouthow you can distinguish the extrover mathematician (looks at YOURshoes when talking to you) but the reality is that mathematics isreally a group activity, and in order to thrive in mathematics you needto learn to step forward and talk to people you don't know. You'regoing to have to ask the faculty a lot of questions in grad school, andI don't just mean about your classes: you're going to have to get in thehabit of knocking on a door and saying, Prof. X, I'm one of the gradstudents here and I've been reading this book about [your specialty] andit makes some references to results in [X's specialty]; could I meet withyou some time and ask you a few questions about this?. I still do thisquite often (except I don't call myself a grad student). Get used to it!Practice it and you'll have an icebreaker for the departmental tea.The nice part about this is that after years of teaching calculus,mathematicians are usually starved for an opportunity to talk aboutsomething in their own area, or some bit of mathematics (or whatever!)that they feel qualified to talk about. If you walk in with someclear questions and the ability to show that you've been making areasonable effort to understand things on your own, your only realchallenge will be to get Prof X to shut up.(Just take a look at this newsgroup; some of us seem to suffer fromlogorrhea!)dave=== === Subject: : Re: Need advice on letters of recommendation> Is there any standard way to go about this? I've had students walk into my office with the letter written for me and asking me to sign it. Let's callthat not standard (and not acceptable.)As others have said, professors do this all the time, andoften for students they barely know, except as a list ofnumbers in a grade book. If you can help make the connectiona bit, that is a good thing. Some students walk in andask for recommendations and then walk out. Later I getsome addresses. OK, I can deal with it, and they get thebest letter I can put together.But other students hand me a little resume of their careers,which helps me immensely. It reminds me that they were inthat production of Othello I enjoyed so much and that theyare always lying next to me when I'm giving blood at the blood drive and it helps me find their records amongst allmy spreadsheets when they've lis the classes they took.Oh, yeah, she DID win that freshman math contest.It helps keep the letter from looking generic.Plus the fact that the student had it together enough tohand me the resume says something in itself. Grad school also takes perserverence, and the letter ought to addressthe student's character if it can. So if I can say somethingpositive that indicates that the student not only has somemathematical talent, but also exhibits the academic maturityfor sticking things out, then I will. The brief inteview you get when asking for the letter is a quick, but importantchance to demonstrate those characteristics.So, my advice is that while you're asking for the recommendation,you connect personally with the professor a bit. It's anopportunity to ask him for advice on the choice of grad schoolsor field of study or tips for getting through and it willhelp him write the letter if he knows you a bit better.Bart=== === Subject: : Re: Need advice on letters of recommendation permission for an emailed response.X-Zippy-Says: I selec E5... but I didn't hear ``Sam the Sham and the Pharaohs''!> I've had students walk into my office with the letter > written for me and asking me to sign it. Let's call> that not standard (and not acceptable.)Eek! The thing to do of course is to agree to write a letter anyway,insist that it be confidential, and then mention the details of thetransaction in the letter.Thomas=== === Subject: : Re: Need advice on letters of recommendation>> I've had students walk into my office with the letter >> written for me and asking me to sign it. Let's call>> that not standard (and not acceptable.)> Eek! The thing to do of course is to agree to write a letter anyway,> insist that it be confidential, and then mention the details of the> transaction in the letter.Well, I should have said student, not students. Andin this case, I trea it as a special situation. First,it was a (very) foreign student. Second, the letter wasonly for a summer job, not an internship or grad school.Third, the situation came up suddenly, where few opportunitiesare available for (very) foreign students and it was a rush job (due that day) and the student thought she was doing me a favor AND was quite polite about it. Fourth, the letterwas accurate and well-written, thanks to a collaborationof some friends. So I had no trouble signing my name toit. I would have written a more glowing letter for her,since she was a stellar student.Then we had a discussion about proper procedure. No harm done. (She _was_ jerking her boyfriend around at the time,so if that character trait manifests itself again in a moreserious situation, then she _will_ get nuked. But it won'tbe because someone wasn't frank with her at least once.)Bart=== === Subject: : Re: Need advice on letters of recommendation permission for an emailed response.X-Zippy-Says: Yow! Am I in Milwaukee?> Well, I should have said student, not students. And> in this case, I trea it as a special situation. First,> it was a (very) foreign student. Second, the letter was> only for a summer job, not an internship or grad school.> Third, the situation came up suddenly, where few opportunities> are available for (very) foreign students and it was a > rush job (due that day) and the student thought she was doing > me a favor AND was quite polite about it. Fourth, the letter> was accurate and well-written, thanks to a collaboration> of some friends. So I had no trouble signing my name to> it. I would have written a more glowing letter for her,> since she was a stellar student.Ah yes, that is a particular singular situation indeed.=== === Subject: : Re: Need advice on letters of recommendation Adjunct Assistant Professor at the University of Montana.>> I've had students walk into my office with the letter >> written for me and asking me to sign it. Let's call>> that not standard (and not acceptable.)>Eek! The thing to do of course is to agree to write a letter anyway,>insist that it be confidential, and then mention the details of the>transaction in the letter.I disagree. There's a chance, at least, that the individual issincerely trying to be helpful. I had, on occasion, had professors Iasked for letters of recommendation tell me to just write it and I'llsign it. Needless to say, I decided to go ask other people forletters when that was the case, and I frown thoroughly on thatpractice. But perhaps the student had encountered a similarlyill-disposed professor, and thought he would save time by bringing aletter ready? Absent other experience, he may well think that it->is<- standard.I would certainly tell the student that the practice is not standard,and should not be acceptable. I would also suggest that any professorof his who has sugges this method to him is NOT a good referencewriter, and he should seek to replace him. And I will usually try torefuse to write letters of recommendation for admission to graduateschool for people that I will not recommend (i.e., people I would notsay good things in balance). That does not mean that my letters do notmention any problems, just that if I have a generally bad opinion ofsomeone, then I recommend to the student to find someone else to writeit. (It's happened once or twice; once, I asked a student who had notdone very well in my class why he was asking me. He explained that hewas seeking to be admit to a specific, applied math program, and hewas hoping that by getting a letter from an algebraist, he would showhis breadth. I sugges he just get letters from applied math and usehis transcripts to show breadth, and he acquiesced. I usually try tosuggest other courses of actions rather than flatly refuse, and oncethe student insis and I said that I would not be able to writeanything glowing, and would point out that on the balance his work had=== === Subject: : Re: Need advice on letters of recommendation> I've had students walk into my office with the letter >> written for me and asking me to sign it. Let's call>> that not standard (and not acceptable.)>>Eek! The thing to do of course is to agree to write a letter anyway,>insist that it be confidential, and then mention the details of the>transaction in the letter.> I disagree. There's a chance, at least, that the individual is> sincerely trying to be helpful. I had, on occasion, had professors I> asked for letters of recommendation tell me to just write it and I'll> sign it. Needless to say, I decided to go ask other people for> letters when that was the case, and I frown thoroughly on that> practice. But perhaps the student had encountered a similarly> ill-disposed professor, and thought he would save time by bringing a> letter ready? Absent other experience, he may well think that it> ->is<- standard.For the most part I disagree with this, but there are certainsituations as you mention where I think this is acceptable. One ofthem is happening to me at present. I am undergraduate, graduating inspring. I am applying for a program which is completely unrela tomathematics, yet two recommendations have to come from professors ofmine. So what's a person to do? I have to get letters ofrecommendation from math professors, but none of them really can saymuch about the skills which should be mentioned in the letter (inparticular, ability to teach, leadership qualities, speaking ability,ability to work under pressure, work ethic, not cracking under thepressure of living in a foreign country for the first time). So Iapproached one professor with whom I have had about 3 advancedclasses, and he thought it would be good to just make stuff up (orrather, stretch the truth a little bit and take qualities he knowsabout me and extend them to qualities he doesn't), but anotherprofessor told me to just write the letter for him and he'd rewrite itin his own voice. His complaint, perfectly valid, is that he had noidea what to say about me for these kinds of qualities. It turned outthe class I had had him for was an upper division class taught usingthe Moore method, so I mentioned lots of stuff in my letter about howI was very eager to go the board all the time, was able to make keenobservations and was one of the leaders of the classroom, goodspeaker when it was my turn at the board, etc. All very honest, buthe simply wasn't used to writing letters of this sort.=== === Subject: : Re: Need advice on letters of recommendation> I disagree. There's a chance, at least, that the individual is> sincerely trying to be helpful. I had, on occasion, had professors I> asked for letters of recommendation tell me to just write it and I'll> sign it. Needless to say, I decided to go ask other people for> letters when that was the case, and I frown thoroughly on that> practice. But perhaps the student had encountered a similarly> ill-disposed professor, and thought he would save time by bringing a> letter ready? Absent other experience, he may well think that it> ->is<- standard.If the student did well in your class but you don't know very muchabout her you can always have a chat with her to get to know herbetter. And you can ask the student for a copy of her resume, too. If you really can't say much specific about the student, even if shedid well in your class, perhaps you shouldn't write the reference.=== === Subject: : Re: Need advice on letters of recommendation>>I've had students walk into my office with the letter >written for me and asking me to sign it. Let's call>that not standard (and not acceptable.)>Eek! The thing to do of course is to agree to write a letter anyway,>>insist that it be confidential, and then mention the details of the>>transaction in the letter.>>I disagree. There's a chance, at least, that the individual is>sincerely trying to be helpful. I had, on occasion, had professors I>asked for letters of recommendation tell me to just write it and I'll>sign it. Needless to say, I decided to go ask other people for>letters when that was the case, and I frown thoroughly on that>practice. But perhaps the student had encountered a similarly>ill-disposed professor, and thought he would save time by bringing a>letter ready? Absent other experience, he may well think that it>->is<- standard.>I would certainly tell the student that the practice is not standard,>and should not be acceptable. I would also suggest that any professor>of his who has sugges this method to him is NOT a good reference>writer, and he should seek to replace him.Perhaps (well, more than perhaps) I am just lazy, but I disagree. It sometimes happens that a student has very few choices amongst referees. This happened to me (as the referee) once. It was thie middle of fall semester, a first-year grad student needed a reference for some scholarship fast, and I had only had him that semester. I looked at the form and what it asked and I knew that I could not knowledgeably answer the questions. I sugges he write a recommendation himself and give it to me. Then I could modify it to what I thought was appropriate. I would certainly not just sign it carte blanche.However, in this case, I also sugges as a better procedure that the student contact professors at his undergraduate department; this is what he did.-- === === Subject: : Re: Need advice on letters of recommendation Adjunct Assistant Professor at the University of Montana.>I am a senior and I will be needing to fill out applications for graduate>school. My problem is that I am on the quarter system and the quarter is about>to end. We will not resume until the beginning of January. I'm pretty shy and>have not asked any of my professors for letters. I'm just not sure how to ask>them and now that I basically have no time left, I was just wondering how I>should go up to them and ask. I have had the same professors for a lot of>classes in some cases but I'm not sure whether or not lower level classes would>give a professor enough to say anything about me. Is there any standard way to>go about this? Most schools seem to want three and for me that is a lot.Asking for letters is about the most uncomfortable thing I've had todo, both when applying for grad school, and now for jobs. The goodnews is that most people are very nice about it.First: do it, and do it SOON. The letters have to be in, and youshould give the professors at least a couple of weeks to do it; as thesemester winds down, a professor's time supply is short. Ask for theletters this week or next, and don't delay.Pick upper division classes in which you did well. They don't all haveto be math classes, but at least one (preferably two) should be.Go to the professor, remind him who you are and how he knows you, andsay simply that you are applying for grad school, and since you didwell in his/her class, you would very much appreciate it if he/shecould could write you a letter of recommendation for yourapplication. Take the forms with you, and be ready with informationabout deadlines and so on. Probably the best is to catch them duringtheir regularly scheduled office hours. If the professor only knows you from lower division courses, it isprobably not a good bet for a letter, but if you had him for bothupper and lower divisions, then feel free to go for it.And, keep this in mind: most professors understand that this is partof their job. If you did well in the class, they will be happy tohelp. === === Subject: : Re: Need advice on letters of recommendationKatie, Your professors are used to writing letters, so don't be afraid tosimply go talk to them and ask. Keep in mind that your professors aremathematicians because they really like math, so they'll generally bevery happy that you're going to continue your studies of theirfavorite subject. The best letters come from professors from whom youhave either taken an advanced course or from whom you have takenmultiple courses.Your professors will know what procedure they like to follow. Mostgrad schools have a separate form that they ask the professor to fillout, plus they ask for a letter. So you'll need to give your professorthe forms from the schools to which you're applying. Your professormay also ask that you to provide an addressed (and stamped) envelopefor them to mail the letter to the grad school. OTOH, some gradschools will have the professor seal his/her letter in an envelope andgive it back to you to include with your application. So you'll needto read the instructions for each application.If you want to make your professors' job a little easier, and alsohelp them write the strongest possible letter for you, then you couldgive them a copy of the essay that you'll be including with your gradschool application. In that essay you'll be explaining, in one form oranother, why you want to go to grad school. [It isn't _necessary_ togive this to your professors, but as someone who has written 100+ suchletters over the past decade or so, I can tell you that I find it veryhelpful. BTW, the same advice applies when you graduate with yourPh.D. and are applying for jobs; the more information you can give toyour letter writers, the better.]Finally, if you won't have time to get these materials to yourprofessors before the quarter ends, then you should definitely go talkto them _now_, and tell them that you'll mail them the materials inDecember. Then assemble the necessary material at home and send it tothem.Good luck with your applications.JoeS=== === Subject: : Re: Need advice on letters of recommendation> I am a senior and I will be needing to fill out applications for graduate> school. My problem is that I am on the quarter system and the quarter is > about> to end. We will not resume until the beginning of January. I'm pretty shy > and> have not asked any of my professors for letters. I'm just not sure how to > ask> them and now that I basically have no time left, I was just wondering how I> should go up to them and ask. I have had the same professors for a lot of> classes in some cases but I'm not sure whether or not lower level classes > would> give a professor enough to say anything about me. Is there any standard way > to> go about this? Most schools seem to want three and for me that is a lot.What worked for me many years ago was to ask the professors of the upper-division classes where I had done well. I agree it can feel a little embarrassing to feel like you have to hustle like this, but the profs are quite accustomed to it, it's part of their jobs. Just pick the three profs who have seen you do your best work, and go to them during office hours and simply ask for a letter. They've done this before and they'll know what to do.=== === Subject: : Re: Need advice on letters of recommendationThanks. I have another (probably stupid) question. If you're applying tomultiple schools and they all want a letter of recommendation, does theprofessor have to print out a lot and sign them all or can I xerox them?Thanks=== === Subject: : Re: Need advice on letters of recommendation>Thanks. I have another (probably stupid) question. If you're applying to>multiple schools and they all want a letter of recommendation, does the>professor have to print out a lot and sign them all or can I xerox them?Usually the department office can handle that; I know that when I was interviewing for professor positions, our graduate secretary handled thedistribution of letters of rec. I just asked for letters, and then toldwhere I wan them to go (I had to label the envelopes, too).=== === Subject: : Re: Need advice on letters of recommendation permission for an emailed response.X-Tom-Swiftie: You've put too much peanut butter on the sandwich, Tom said thickly> Thanks. I have another (probably stupid) question. If you're applying to> multiple schools and they all want a letter of recommendation, does the> professor have to print out a lot and sign them all or can I xerox them?When I applied to grad school (not in math, but the procedure isbasically the same regardless), each school had a separaterecommendation form.I provided each professor with a labelled envelope, the form for eachschool to which I was applying. I had filled out the applicantportion of each form and as much of the recommender portion as madesense, and then gave each professor their stack.Most of the schools wan the recommenders to mail theirrecommendations directly to the school; for those, the labelledenvelope was completely addressed and stamped. Other schools wanthe recommenders to give sealed signed-across-the-flap envelopes tothe applicant, and for that purpose I gave the professor a largeenvelope addressed to me to put them all in and drop in the mail tome.I made it my responsibility to do as much as I could to minimize thehassle on the part of the recommenders, while being careful topreserve the confidentiality of the recommending process. Thomas=== === Subject: : Re: Need advice on letters of recommendation> I provided each professor with a labelled envelope, tYeah, that's about the extent of it. You want to make their job as easyas possible, but there is tto much variation. But I write my letters inWord (heresy!) anyway, so with cut and paste that part is not too muchtrouble. You might offer to send them the addresses over email so thatthey can cut/paste that if they write the letters electronically.V.-- email: lastname at cs utk eduhomepage: cs utk edu tilde lastname=== === Subject: : Re: Need advice on letters of recommendation> Thanks. I have another (probably stupid) question. If you're applying to> multiple schools and they all want a letter of recommendation, does the> professor have to print out a lot and sign them all or can I xerox them?Ask someone in the math department office, for example the office manager. As I recall, they didn't give me my letters, in fact I never saw them. You just tell the prof what schools and the rest gets handled somehow.=== === Subject: : Cantor Enumeration for ZZ^3Dear Readers,does anybody know an explicit bijective map IN -> ZZ^3 (for computation in MAGMA)?Your help would be much apprecia.Guido=== === Subject: : Re: Cantor Enumeration for ZZ^3>Dear Readers,>does anybody know an explicit bijective map IN -> ZZ^3 >(for computation in MAGMA)?> Start withan explicit bijection f between N and Z (you can code the sequence 0,1,-1,2,-2,3,-3, ... using (-1)^n judiciously)an explicit bijection g between N and N^2, e.g., n -> (g1(n),g2(n)), where n = 2^(g1(n)) * (2*g2(n)+1)then n -> (g1(n),g2(n)) -> (g1(n),g1(g2(n)),g2(g2(n))) -> (f(g1(n)),f(g1(g2(n))),f(g2(g2(n))))shows how to compose these into the desired bijection.Note: g1(n)=floor(2log(n)) and g2(n)=(n*2^(-g1(n))-1)/2KP-- E-MAIL: K.P.Hart@EWI,TUDelft,NL PAPER: Faculty EWIPHONE: +31-15-2784572 TU DelftFAX: +31-15-2786178 Postbus 5031URL: http://aw.twi.tudelft.nl/~hart 2600 GA Delft the Netherlands=== === Subject: : OPE BookI am looking for supplemental text to aid in my learning of ODE andPDE next semester. Currently my undergraduate text is ElememntaryDifferential Equations with Boundry Value Problems by Derrick andGrossman. Ideally, I would appreciate an text which emphsizestheoretical foundation over applied examples. Any suggestions aregreatly apprecia.Thanks.Owen=== === Subject: : Re: OPE Book> I am looking for supplemental text to aid in my learning of ODE and> PDE next semester. Currently my undergraduate text is Elememntary> Differential Equations with Boundry Value Problems by Derrick and> Grossman. Ideally, I would appreciate an text which emphsizes> theoretical foundation over applied examples. Any suggestions are> greatly apprecia.how about two books?1. _ordinary differential equations_ by wolfgang waltera well-balanced emphasis on both theory and applications2. _partial differential equations_ by fritz johnpleasant development of the theoryor2'. _partial differential equations: an introduction_ by walter strauss> Thanks.> Owen=== === Subject: : Re: OPE Book>I am looking for supplemental text to aid in my learning of ODE and>PDE next semester. Currently my undergraduate text is Elememntary>Differential Equations with Boundry Value Problems by Derrick and>Grossman. Ideally, I would appreciate an text which emphsizes>theoretical foundation over applied examples. Any suggestions are>greatly apprecia.Wow, that's a refreshing change: most students these days are lookingfor lots of examples and no theory.You might look at M. Braun, Differential Equations and Their Applications, Applied Mathematical Sciences 15, Springer-Verlag 1975.Or a somewhat more challenging one: G. Birkhoff and G.-C. Rota, Ordinary Differential Equations, Ginn 1962.Robert Israel israel@math.ubc.caDepartment of Mathematics http://www.math.ubc.ca/~israel University of British Columbia Vancouver, BC, Canada V6T 1Z2=== === Subject: : Re: Question about a C^infty functionThe police and so forth only exist insofar as they can demonstratetheir authority. They say they're here to preserve order, but in factthey'd go absolutely mad if all the criminals of the world went onstrike for only a month. They'd be on their knees waiting for acrime. That's the only existence they have.William S. Burroughs (American writer) Guardian, 1966huffy=== === Subject: : Re: Question about a C^infty functionThe police and so forth only exist insofar as they can demonstratetheir authority. They say they're here to preserve order, but in factthey'd go absolutely mad if all the criminals of the world went onstrike for only a month. They'd be on their knees waiting for acrime. That's the only existence they have.William S. Burroughs (American writer) Guardian, 1966huffy=== === Subject: : Re: Question about a C^infty functionThe police and so forth only exist insofar as they can demonstratetheir authority. They say they're here to preserve order, but in factthey'd go absolutely mad if all the criminals of the world went onstrike for only a month. They'd be on their knees waiting for acrime. That's the only existence they have.William S. Burroughs (American writer) Guardian, 1966huffy=== === Subject: : Re: Question about a C^infty function> The police and so forth only exist insofar as they can demonstrate> their authority. They say they're here to preserve order, but in fact> they'd go absolutely mad if all the criminals of the world went on> strike for only a month. They'd be on their knees waiting for a> crime. That's the only existence they have.> William S. Burroughs (American writer)> Guardian, 1966(off-topic)When I heard that Bill Burroughs had died, I immediately askedhow could they tell?.(apologies to Dorothy Parker)-- === === Subject: : Re: Banach limit and almost convergenceThe police and so forth only exist insofar as they can demonstratetheir authority. They say they're here to preserve order, but in factthey'd go absolutely mad if all the criminals of the world went onstrike for only a month. They'd be on their knees waiting for acrime. That's the only existence they have.William S. Burroughs (American writer) Guardian, 1966huffy=== === Subject: : Re: Banach limit and almost convergence>Hi!>It was no several times in Google Groups (by Ronald Bruck), then>uniqueness of Banach limit of a sequence is equivalent to almost>convergence of this sequence. Can you give me a hint where to find a>proof of this result. (Web resources are prefered, but also book or>paper in a journal would help.)> Have you tried searching the _web_ using Google? If you type> Banach limit almost convergence> into the search box you get a few hits, one of which says this> result was proved by Lorentz in A contribution to the theory> of divergent sequences, Acta Math 80(1948).>Thanks in advance!>Martin Sleziak>The police and so forth only exist insofar as they can demonstratetheir authority. They say they're here to preserve order, but in factthey'd go absolutely mad if all the criminals of the world went onstrike for only a month. They'd be on their knees waiting for acrime. That's the only existence they have.William S. Burroughs (American writer) Guardian, 1966huffy=== === Subject: : Re: Banach limit and almost convergenceContent-transfer-encoding: 8bit>Hi!>It was no several times in Google Groups (by Ronald Bruck), then>uniqueness of Banach limit of a sequence is equivalent to almost>convergence of this sequence. Can you give me a hint where to find a>proof of this result. (Web resources are prefered, but also book or>paper in a journal would help.)> Have you tried searching the _web_ using Google? If you type> Banach limit almost convergence> into the search box you get a few hits, one of which says this> result was proved by Lorentz in A contribution to the theory> of divergent sequences, Acta Math 80(1948).Thank you, David. But with this big a hint, one ought to be able toprove it oneself. As is common, it's discovering the STATEMENT TO BEPROVED which is the original contribution and the hard part. I supposethat Fermat's Last Theorem is an exception to the rule--Ron Bruck=== === Subject: : Re: There are no other solutions... how to prove it?> how can I prove that the ONLY solutions of the ODE> y'' = -y are the ones given by A cos(x) + B sin(x) ?Easy: Wronskian W(cos,sin) = cos^2 + sin^2 = 1 != 0, soVariation of Parameters (2) specialized to _homogeneous_ case shows that any other solution is a linear combination of cos, sin with _constant_ coef's. Below are easy proofs,which generalizes to higher-order LODEs (and recurrences).The proof is slicker in matrix form, e.g. Lemma 4.1 in (3).THEOREM If f,g,h are solutions on an interval I of the LODE y'' = p y' + q y, p,q continuous on Iand gh'-g'h != 0 for all x in I, then there exist constants c,dsuch that f = c g + d h on IPROOF: The below equations [0],[1] have a unique solution (c,d)since det = W(g,h) = gh'- g'h != 0 on I.[0] f = c g + d h[1] f' = c g' + d h'[2] qf+pf' = f = c g + d h via q[0]+p[1], g=qg+pg', h=qh+ph'[3] 0 = c'g + d'h via [0]'-[1][4] 0 = c'g' + d'h' via [1]'-[2] (1b)The above equations [3],[4] have unique solution (c',d') = (0,0)since det = gh'-g'h = W(g,h) != 0 on I. Thus c,d are constants.-------THEOREM If f,g,h are solutions of the recurrence y'' = p y' + q y, where y'(n) := y(n+1)with Wronskian W = gh'-g'h != 0 then there exist constants c,dsuch that f = c g + d hPROOF: [0],[1] below have unique solution (c,d) via det = W != 0[0] f = c g + d h[1] f' = c g' + d h' Now q[0] + p[1] yields:[2] qf+pf' = f = c g + d h via qg+pg' = g, qh+ph' = h[3] 0 = (c'-c)g' + (d'-d)h' via [0]'-[1][4] 0 = (c'-c)g + (d'-d)h via [1]'-[2]The above equations [3],[4] have solution (c'-c,d'-d) = (0,0),unique via det = W' = g'h-gh' != 0. So c,d are constants,since c' = c means c(n+1) = c(n).-Bill Dubuque(1) L. E. Pursell: A simple uniqueness theory for ordinary linearhomogeneous differential equations, Amer. Math. Monthly, 74, 1967, 47-50 http://links.jstor.org/sici?sici=0002-9890(196701)74:1%3C47%3E (2) Variation of Parametershttp://planetmath.org/encyclopedia/ VariationOfParameters.htmlhttp://ltcconline.net/greenl/courses /204/appsHigherOrder/variationHigher.htm(3) Marius van der Put: Symbolic analysis of differential equationshttp://msri.org/activities/programs/9899/focm/soggy/ MSRIintro/van_der_Put2.psd:Symbolic analysis of differential equations -- Put.ps.gz=== === Subject: : Re: if x has normally distribu digits, does 1/x?>> If so, how do you prove its normality?>He can't. That's why he said it was his guess, not his theorem. Well at least it would be nice to get an idea why such a reciprocalwould be normal.>No one knows how to prove pi is normal, but the smart money >is all riding on that guess. Same for the sugges number.Smart money? Did I miss the JSH lecture of marketing in mathematicsagain?=== === Subject: : Re: if x has normally distribu digits, does 1/x?> If so, how do you prove its normality?>>He can't. That's why he said it was his guess, not his theorem. > Well at least it would be nice to get an idea why such a reciprocal> would be normal.>No one knows how to prove pi is normal, but the smart money >is all riding on that guess. Same for the sugges number.> Smart money? Did I miss the JSH lecture of marketing in mathematics> again?The set of non-normal numbers has Lebesgue measure zero. If you pick a real uniformly at random from the interval [0, 1] then with probability 1 you have picked a normal number. This leads many to take the position that if some number pops up somewhere & there's no good reason to think it's not normal - some number like pi, or like the reciprocal of the number you get when you replace every other digit in the decimal expansion of pi with a zero - then it's safe to assume that the number is normal. Safe to assume doesn't mean we know how to prove, and I don't know what JSH has to do with it as I stopped reading his threads years ago.-- === === Subject: : Axiom of Foundation (absymally stupid question)Hi folks,Okay, this is going to be some very stupid question to most of you.The axiom of foundation says that: ForAll B ~= emptyset, ThereExists y in B such that (y intersect B)=emptyset.Now suppose B = {lime, orange, lemon}. What is such y among this setof citruses? Suppose y = lime. How can lime be a set? (myunderstanding is that only sets can intersect).I told you, it is a stupid question. But I want to know.=== === Subject: : Re: Axiom of Foundation (absymally stupid question)The whole problem is just that you're misquoting the axiom. You say: Everynonempty B contains a y with (B intersect y) = empty. I say: Every nonempty Bcontains a y for which there is no z with z in y and z in B. My axiom sayssubstantially the same thing, but it allows for the possibility that there existcitrus fruits that are not sets. Alternatively, you could banish such citrusfruits from your theory. Citrus fruits that have no elements, but aren't theempty set, are technically called individuals. Whether you want them to existor not is basically a matter of taste, which I suppose would have to be fairlysour. HTH| Hi folks,|| Okay, this is going to be some very stupid question to most of you.|| The axiom of foundation says that:|| ForAll B ~= emptyset, ThereExists y in B such that (y intersect B)=| emptyset.|| Now suppose B = {lime, orange, lemon}. What is such y among this set| of citruses? Suppose y = lime. How can lime be a set? (my| understanding is that only sets can intersect).|| I told you, it is a stupid question. But I want to know.=== === Subject: : Re: Axiom of Foundation (absymally stupid question)>Citrus fruits that have no elements, but aren't the>empty set, are technically called individuals. >Whether you want them to exist>or not is basically a matter of taste, >which I suppose would have to be fairly>sour. HTHIs that a consequence of Zorn's Lemon?Lee Rudolph=== === Subject: : Re: Axiom of Foundation (absymally stupid question)> Hi folks,> Okay, this is going to be some very stupid question to most of you.> The axiom of foundation says that: > ForAll B ~= emptyset, ThereExists y in B such that (y intersect B)=> emptyset.> Now suppose B = {lime, orange, lemon}. What is such y among this set> of citruses? Suppose y = lime. How can lime be a set? (my> understanding is that only sets can intersect).> I told you, it is a stupid question. But I want to know.It's not stupid, just based on a bit of a confusion between formal and intuitive set theory.The thing about formal set theory (or at least ZFC formal set theory - I think there are versions where this isn't true) is that *everything* is a set. For example 0 = empty set, 1 = {0}, 2 = {0, 1}, etc. You define the natural numbers in terms of sets, and then build up from there. When things get complica enough things stop *looking* like sets - for example writing down the real number 1 as a set would be highly non-trivial (and very dependent on how you construc the real numbers), but the point remains that at some fundamental level they are still sets.So you couldn't form a set like B = {lime, orange, lemon}, because limes, oranges and lemons aren't sets (well, you could give the name 'lime' to a set, but it would still be a set).Hope that helps,David=== === Subject: : Re: Axiom of Foundation (absymally stupid question)Jared> The axiom of foundation says that:> ForAll B ~= emptyset, ThereExists y in B such that (y intersect B)=> emptyset.> Now suppose B = {lime, orange, lemon}. What is such y among this set> of citruses? Suppose y = lime. How can lime be a set? (my> understanding is that only sets can intersect).lime intersect B = emptysetMaybe the confusion is due tolime <> {lime}and indeed{lime} intersect B <> emptyset.LH=== === Subject: : Re: Usenet Posting Guide?> (snip)> Not to get into a flame war, but coming from sci.math> I have to object to what seems to me to be some false> theorems in your reasoning, namely that> politically liberal => PETA> Sierra Club => environmental terrorist> environmentalist => every wacko animal rights sentiment> I would describe myself as a political liberal and an> environmentalist (to the point of bicyling across> adelphia to work on occasion). But I don't> identify with anything on the right hand side.> I refuse to get into an argument about my positions,> or yours. I just want to point out that you have> dismissed the other side of the political spectrum> as not being a spectrum.> - Randy> Randy, dear boy, if I might jump in here, it's rather quite axiomatic> that liberals never identify themselves as being liberal in their> politicsReally? Liberals never call themselves liberal? Areyou sure? How do you read the sentence beginningI would describe myself...? Just curious, if you'regoing to throw words like axiomatic around.> the presumption being that liberals by definition (their> definition, BTW) are open to all views they see as reasonable (again,> their definition of what's reasonable).So you would say all liberals consider themselves opento, say, Ann Coulter or Rush Limbaugh? Where are yougetting this from?> As for your above equations, they ignore the larger reality that most> PETA freaks are overwhelmingly liberal in their politics.No they don't. Again, I'm not going to get into a politicalwar, just commenting on the error in logic. Your statementis that A => B, where A is person X is a PETA freakand B is person Y is a liberal.That does not in any way mean that B => A.> So, too, is> the white wine and brie crowd who by and large make up the Sierra Club> constituency. As for the environmentalists, as a group, if anything> they're even worse than liberals in their politics, the vast majority> of them being Bolsheviks.Bolsheviks? Are you a fan of Tom Potter? He's the onlyother person I know to use that term to describe peoplepost-1920 or so.> No, dear man, these people can be called a> lot of things, but conservative or republican aren't numbered among> them.Nor did I imply that it should be.Consider the phrase political spectrum. The politicalspectrum is actually a multivariate space, and there's lotsof room in the quadrant called liberal to separateenvironmentalist from eco-terrorist or PETA freak.Again you seem to be making the same logical error(s)that cause you to be unable to recognize that people,even liberal people, have multiple attributes thatdistinguish their political views.By the way, I'll also point out that democrat/republicanis not equivalent to liberal/conservative, thoughthere is certainly a high degree of correlation. Up tilla couple of years ago, I lived in a liberal congressionaldistrict in a liberal state with a well-loved Republicancongressional representative.In fact, prior to the early 80s, I identified myself asa liberal Republican. - Randy=== === Subject: : Re: Usenet Posting Guide?> So, too, is> the white wine and brie crowd who by and large make up the Sierra Club> constituency. As for the environmentalists, as a group, if anything> they're even worse than liberals in their politics, the vast majority> of them being Bolsheviks.> Bolsheviks? Are you a fan of Tom Potter? He's the only> other person I know to use that term to describe people> post-1920 or so.It is interesting to see that this poster thinks that the Bolsheviks just vanished into nothingness.The fact of the matter is that the Bolsheviks instiga the class wars of the 1900's for power and wealth, and after their class wars were discredi, and the Native Russians regained controlled of their government, millions of the Bolsheviks who had lived high and mighty in Russia, migra to Israel and New York, from where they are instigating the religious wars of the 2000's to get back into the chips as the loot from their class wars is almost gone.I suggest that intelligent, rational, moral folks, reject the media brainwashing, open their eyes, look around and see who instiga the class wars, who is instigating the religious wars, and who profits from both, while others, such as Blacks, Rednecks and Latinos, sacrifice their lives, limbs, liberties and fortunes to fight folks they would otherwise get along with just fine.As can be seen by studying history, and by observing current events, the Bolsheviks have a long history of for power and wealth.Instigating conflict and war is the stock in trade of the Bolsheviks, much as fortune telling is the stock in trade of Gyspies.--Tom Potter http://tompotter.us=== === Subject: : Re: Usenet Posting Guide?> So, too, is> the white wine and brie crowd who by and large make up the Sierra Club> constituency. As for the environmentalists, as a group, if anything> they're even worse than liberals in their politics, the vast majority> of them being Bolsheviks.> Bolsheviks? Are you a fan of Tom Potter? He's the only> other person I know to use that term to describe people> post-1920 or so.> It is interesting to see that this poster thinks > that the Bolsheviks just vanished into nothingness.> The fact of the matter is that the Bolsheviks instiga the > class wars of the 1900's for power and wealth, > and after their class wars were discredi, > and the Native Russians regained controlled > of their government, millions of the Bolsheviks > who had lived high and mighty in Russia, > migra to Israel and New York, from where > they are instigating the religious wars of the 2000's > to get back into the chips as the loot from their class wars > is almost gone.> I suggest that intelligent, rational, moral folks, > reject the media brainwashing, open their eyes, > look around and see who instiga the class wars, > who is instigating the religious wars, > and who profits from both, > while others, such as Blacks, Rednecks and Latinos, > sacrifice their lives, limbs, liberties and fortunes > to fight folks they would otherwise get along with just fine.> As can be seen by studying history, > and by observing current events, > the Bolsheviks have a long history of > for power and wealth.> Instigating conflict and war is the stock in trade > of the Bolsheviks, much as fortune telling > is the stock in trade of Gyspies.Tom, I believe you and I are also on the same page here as it reflectsa proper understanding of Bolshevism. These ill-tutored twits who seethemselves as sophistica and schooled in world politics generallydon't know their gluteous maximus from a hole in the ground. Theseclueless suckers love to snicker at things they know absolutelynothing about. This whole system is crumbling right before their veryeyes, and it's bread and circuses as usual for these politicalgeniuses while race is set against race, class is set against class,gender is set against gender and we all get sold down the river for 30pieces of silver. We're in meltdown and these fools are asleep at thecontrol panel.I liked the OP's comments about the environmental white wine and briecrowd, for they are truly the useful idiots in this whole equation whodo the most damage.=== === Subject: : Re: Usenet Posting Guide?>> So, too, is>> the white wine and brie crowd who by and large make up the Sierra Club>> constituency. As for the environmentalists, as a group, if anything>> they're even worse than liberals in their politics, the vast majority>> of them being Bolsheviks.>> Bolsheviks? Are you a fan of Tom Potter? He's the only>> other person I know to use that term to describe people>> post-1920 or so.Randy, you're right!-- === === Subject: : Re: Usenet Posting Guide?>> So, too, is>> the white wine and brie crowd who by and large make up the Sierra Club>> constituency. As for the environmentalists, as a group, if anything>> they're even worse than liberals in their politics, the vast majority>> of them being Bolsheviks. Bolsheviks? Are you a fan of Tom Potter? He's the only>> other person I know to use that term to describe people>> post-1920 or so.> > Randy, you're right!Just curious Robin.You seem to be a pretty bright boy, what compeled you to make this comment?Do you, or did you, have some kind of relationship with the people who instiga the class wars of the 1900's?I assume that you understand correlations, and have thought a little about the existence of things, including objects and non-objects.Have you ever correla what people, or what groups of people have been central to most conflict and war, particularly the class wars of the 1900's and the religious wars of the 2000's?How do you explain the extinction of an object or a non object, such as an idea?As you may know, the Bolsheviks were not only central to the class wars of the 1900's, they held most of the power positions in Russia up to the present time.After their class wars were discredi, and the loyal Russians began to retake control of the government (A battle which is still going on, as can be seen from recent news reports.), hundreds of thousands of the sons and daughters of the former Russian leadership migra to Israel and New York, where they are up to their old tricks. Do you think that the ideas and tactics of the Bolsheviks simply vanished into nothingness?I assert that:1. Populations exist.2. Populations are quantum entities.3. Contiguous populations form an environment.4. Populations increase exponentially in a nurturing environment.5. Populations decrease exponentially in a non-nurturing environment.6. An event is a population change.Do you know what happens to the objects and the fission or fusion non-objects when events occur?If you think objects and ideas can simply vanish without a trace, please explain how it happens, and when one knows that the final quantum has vanished.--Tom Potter http://tompotter.us=== === Subject: : Re: Usenet Posting Guide?>> So, too, is> the white wine and brie crowd who by and large make up the Sierra> Club constituency. As for the environmentalists, as a group, if> anything they're even worse than liberals in their politics, the> vast majority of them being Bolsheviks.Bolsheviks? Are you a fan of Tom Potter? He's the only> other person I know to use that term to describe people> post-1920 or so.>> Randy, you're right!Randy, you're right squared!!-- === === Subject: : Re: Usenet Posting Guide?>Subject: Re: Usenet Posting Guide?>Message-id: > So, too, is> the white wine and brie crowd who by and large make up the Sierra Club> constituency. As for the environmentalists, as a group, if anything> they're even worse than liberals in their politics, the vast majority> of them being Bolsheviks.Bolsheviks? Are you a fan of Tom Potter? He's the only> other person I know to use that term to describe people> post-1920 or so.>Did you notice how Potter but into this thread with his boiler-platebull? He mentioned once that he doesn't sit around _reading_ sci.math butthat he regularly does searches on his own name to see if anyone is talkingabout him behind his back.If you want to keep his odius presence out of the discussion, it would be bestto take an example from that other Potter and dare not speak his name. Isuggest referring to him in a way to frustrate his search engine, such asT_o_m_P_o_t_t_e_rOf course, he'll probably start looking for _this_ pattern, so pick some othervariation. If he shows up, then he's caught on to that pattern, so switch toanother.>Randy, you're right!>-- >>Needless to say, I had the last laugh.> Alan Partridge, _Bouncing Back_ (14 times)--=== === Subject: : I'm reviewing Calc3-need integral help.I'm having trouble setting up these 3 integrals. Let S be the integralsymbol.1) Evaluate the integral SS (over R) dA/(1 + X^2 + Y^2)^2 over the regionenclosed by one loop of the lemniscate (X^2 + Y^2)^2 - (X^2 -Y^2) =0.2) Find the surface area of the portion of the sphere X^2 + Y^2 + Z^2 = 16between the planes Z = 1 and Z = 2.3)Find the volume cut from the solid sphere X^2 + Y^2 + Z^2 = a^2 by thecylinder r = a * sin (theta).Thanks.=== === Subject: : Re: I'm reviewing Calc3-need integral help.> I'm having trouble setting up these 3 integrals. Let S be the integral> symbol.> 1) Evaluate the integral SS (over R) dA/(1 + X^2 + Y^2)^2 over the region> enclosed by one loop of the lemniscate (X^2 + Y^2)^2 - (X^2 -Y^2) =0.Use plane polars (x = r cos(phi), y = r sin(phi), dA = r dr d(phi) )[Hint: substitute u = r^2, take the limits of the theta integral as-(pi)/4, pi/4]> 2) Find the surface area of the portion of the sphere X^2 + Y^2 + Z^2 = 16> between the planes Z = 1 and Z = 2.Use cylindrical polars (x = r cos(phi), y = r sin(phi), z = z,dA = r d(phi) dz )> 3)Find the volume cut from the solid sphere X^2 + Y^2 + Z^2 = a^2 by the> cylinder r = a * sin (theta).Use spherical polars ( x = r cos(phi) sin(theta),y = r sin(phi) sin(theta), z = r cos(theta),dx dy dz = r^2 sin(theta) dr d(theta) d(phi) )(I'm not sure r = a *sin(theta) is a cylinder; I think the cylinder isgiven by a = r *sin(theta) [ x^2 + y^2 = a^2, -oo < z < oo ] )-- === === Subject: : Re: Fastest factorial algorithm> What is the fastest algorithm for computing factorial, for very large > numbers (e.g. 10000!)?> Normally this would take n-2 multiplications, by multiplying out each > term n(n-1)(n-2)(n-3)...3.2. Is a better way known?Just do the multiplications carefully in the right order. Multiplying k-digit numbers takes O(k log k) time using the best known algorithms, and obviously requires at least O (k) time. If you start with 1, multiply by 2, multiply by 3, and so on, the numbers involved get larger and larger, so the time will be O (n^2 log^2 n). Instead you should use a binary tree for the multiplications: To find the product of k numbers for k > 2, divide the numbers into two sets of equal size, calculate the product of the numbers in the first set, the product of the numbers in the second set, and multiply the products. That way, you should be able to calculate n! in O (n log^3 n). (Actually, I wouldn't count 10000 as a very large number)=== === Subject: : Re: Fastest factorial algorithmX-ID: Tbl9NaZ1we++y9QKom6kuOERHmzG5xwqLk5ZS+wfxmx9HlTWqmzpYu> What is the fastest algorithm for computing factorial, for very large> numbers (e.g. 10000!)?>(...)> (Actually, I wouldn't count 10000 as a very large number)Yes, but what about the OP's 10000! Gottfried Helms=== === Subject: : Re: Fastest factorial algorithm> What is the fastest algorithm for computing factorial, for very large> numbers (e.g. 10000!)?(...)> (Actually, I wouldn't count 10000 as a very large number)> Yes, but what about the OP's 10000! I believe what Christian meant was: I wouldn't count 10000 as a very large number [to compute the factorial for].Computing 10000! using the straightforward algorithm in bc takes only about 13.8 seconds on a 600MHz Pentium III machine I have lying around. And of course, bc isn't what I'd call a speed demon.-M-- http://www.dartmouth.edu/~sting/ | Dartmouth College, Hanover, NH, USA=== === Subject: : Re: Fastest factorial algorithm E29yc_kQC&^> What is the fastest algorithm for computing factorial, for very large> numbers (e.g. 10000!)?(...)> (Actually, I wouldn't count 10000 as a very large number)> Yes, but what about the OP's 10000! That's large itself, but it doesn't take long tocompute. computing 10000!! isn't feasible whatever algorithmyou use.-- J.97n Fairbairn Jon.Fairbairn@cl.cam.ac.uk=== === Subject: : Re: Fastest factorial algorithm>> Yes, but what about the OP's 10000! >That's large itself, but it doesn't take long to>compute. computing 10000!! isn't feasible whatever algorithm>you use. True [at least for (10000!)!, as opposed to the Mathematicameaning]. OTOH, its last 10000!/4 or so digits are easy to calculate,at least to base 10, which gets you part of the way; and so are thefirst few digits. It's just those in the middle that are hard ....-- Andy Walker, School of MathSci., Univ. of Nott'm, UK.anw@maths.nott.ac.uk=== === Subject: : Re: Fastest factorial algorithm E29yc_kQC&^>> Yes, but what about the OP's 10000! >That's large itself, but it doesn't take long to>compute. computing 10000!! isn't feasible whatever algorithm>you use.> True [at least for (10000!)!, as opposed to the Mathematica> meaning]. OTOH, its last 10000!/4 or so digits are easy to calculate,> at least to base 10, which gets you part of the way; and so are the> first few digits. It's just those in the middle that are hard ....I wasn't thinking so much of the difficulty, as where to storethem when you're done.-- J.97n Fairbairn Jon.Fairbairn@cl.cam.ac.uk=== === Subject: : Re: Fastest factorial algorithm>> computing 10000!! isn't feasible whatever algorithm>>you use.>> True [at least for (10000!)!, as opposed to the Mathematica>> meaning]. OTOH, its last 10000!/4 or so digits are easy to calculate,>> at least to base 10, which gets you part of the way; and so are the>> first few digits. It's just those in the middle that are hard ....>I wasn't thinking so much of the difficulty, as where to store>them when you're done. Well, I've saved you a few, 'cos you don't really need tostore the insignificant zeros. The number of digits is only aroundthe 3/2 power of the number of different games of chess, so oncechess is completely solved, this could be the next project ... justneeds a bigger bit-bucket. Or you could think laterally: in base10000!!, the answer is just 10. [But there is no base in which itis 42, sadly.]-- Andy Walker, School of MathSci., Univ. of Nott'm, UK.anw@maths.nott.ac.uk=== === Subject: : Re: Fastest factorial algorithm What is the fastest algorithm for computing factorial, for very large>> numbers (e.g. 10000!)?>> (...) (Actually, I wouldn't count 10000 as a very large number)>> Yes, but what about the OP's 10000! > That's large itself, but it doesn't take long to> compute. computing 10000!! isn't feasible whatever algorithm> you use.Actually, 10000!! is easy, using Mathematica. The !! notationrepresents the double factorial function, such that n!! =n*(n-2)*(n-4)*....I think you meant (10000!)!, which is a bit larger.-- Dave SeamanJudge Yohn's mistakes revealed in Mumia Abu-Jamal ruling.=== === Subject: : Re: Fastest factorial algorithm E29yc_kQC&^> Actually, 10000!! is easy, using Mathematica. The !! notation> represents the double factorial function, such that n!! => n*(n-2)*(n-4)*....I wasn't aware of that usage.> I think you meant (10000!)!,I did indeed.> which is a bit larger.Several bits.-- J.97n Fairbairn Jon.Fairbairn@cl.cam.ac.uk === Subject: : Re: Fastest factorial algorithm <3FB37A98.1E6E3DCF@uni-kassel.de> ===> Actually, 10000!! is easy, using Mathematica. The !! notation> represents the double factorial function, such that n!! => n*(n-2)*(n-4)*....> I wasn't aware of that usage.I think it bogus and that 10000!! means just what you sayit means and for those who insist it means 10000(!!), letthem make it known they're omiting those '(' and ')'!!> I think you meant (10000!)!,> I did indeed.=== === Subject: : Re: Fastest factorial algorithmActually, 10000!! is easy, using Mathematica. The !! notation> represents the double factorial function, such that n!! => n*(n-2)*(n-4)*....I wasn't aware of that usage.I think it bogus and that 10000!! means just what you say> it means and for those who insist it means 10000(!!), let> them make it known they're omiting those '(' and ')'!!The double factorial is a standard (and, in my experience, useful)notation. It is hardly bogus.David Cantrell> I think you meant (10000!)!,I did indeed.=== === Subject: : Re: Fastest factorial algorithm>Actually, 10000!! is easy, using Mathematica. The !! notation> represents the double factorial function, such that n!! => n*(n-2)*(n-4)*....I wasn't aware of that usage.I think it bogus and that 10000!! means just what you say> it means and for those who insist it means 10000(!!), let> them make it known they're omiting those '(' and ')'!!> The double factorial is a standard (and, in my experience, useful)> notation. It is hardly bogus.Usefulness of the double-factorial function aside, the notation is, in my not-so-humble opinion, an unintuitive abomination that should have been stamped out before it took hold.Does anyone know who first coined that notation?-- Unpatched IE vulnerability: WMP local file bounceDescription: Switching security zone, arbitrary command execution, automatic email-borne command executionReference: http://www.ntbugtraq.com/default.asp?pid=36&sid=1&A2=ind0307&L =ntbugtraq&F=P&S=&P=6783Exploit: http://www.malware.com/once.again!.html=== === Subject: : Re: Fastest factorial algorithm>> Actually, 10000!! is easy, using Mathematica. The !! notation>> represents the double factorial function, such that n!! =>> n*(n-2)*(n-4)*....> I wasn't aware of that usage.>> I think it bogus and that 10000!! means just what you say>> it means and for those who insist it means 10000(!!), let>> them make it known they're omiting those '(' and ')'!! > The double factorial is a standard (and, in my experience, useful)> notation. It is hardly bogus.I'll agree that the double factorial can be quite useful, but I'llnot go so far as to say that the _notation_ is useful. When one firstencounters something such as 10000!!, everyone no doubt assumes it tomean (10000!)! instead of the double factorial. Perhaps if everyoneput their minds to it, someone could invent a more intuitivenotation (or at the very least, not negatively intuitive). Perhaps ?will work? Or maybe &!?----------------------------------------------------------- ---------- | Good and evil both increase at compoundBen Hocking, Grad Student | interest. That is why the littlehocking@cs.virginia.edu | decisions you and I make every day are of | such infinite importance. - C. S. Lewis--------------------------------------------------------- ------------=== === Subject: : Re: Fastest factorial algorithm>> Actually, 10000!! is easy, using Mathematica. The !! notation>> represents the double factorial function, such that n!! =>> n*(n-2)*(n-4)*....> I wasn't aware of that usage.>> I think it bogus and that 10000!! means just what you say>> it means and for those who insist it means 10000(!!), let>> them make it known they're omiting those '(' and ')'!!> The double factorial is a standard (and, in my experience, useful)> notation. It is hardly bogus.> I'll agree that the double factorial can be quite useful, but I'll> not go so far as to say that the _notation_ is useful.I grant that the notation is an unfortunate one. But there are several ofthose in mathematics.On the board:dy--dxHey, prof, why don't you reduce the fraction to y/x by cancelling the d's?> When one first> encounters something such as 10000!!, everyone no doubt assumes it to> mean (10000!)! instead of the double factorial. Perhaps if everyone> put their minds to it, someone could invent a more intuitive> notation (or at the very least, not negatively intuitive). Perhaps ?> will work? Or maybe &!?Here's one idea. For the double factorial, place a subscript of 2 on thefactorial sign. For example, 10000!_2. For the triple factorial, use asubscript of 3; etc.But even if such a notation were to become popular, the previous notation,now well established, would most likely persist. Then we'd have _two_notations, causing even more confusion perhaps...David=== === Subject: : Re: Fastest factorial algorithmDistribution: inet Actually, 10000!! is easy, using Mathematica. The !! notation>> represents the double factorial function, such that n!! =>> n*(n-2)*(n-4)*....>> I think it bogus and that 10000!! means just what you say>> it means and for those who insist it means 10000(!!), let>> them make it known they're omiting those '(' and ')'!!> The double factorial is a standard (and, in my experience, useful)> notation. It is hardly bogus.> I'll agree that the double factorial can be quite useful, but I'll> not go so far as to say that the _notation_ is useful. When one first> encounters something such as 10000!!, everyone no doubt assumes it to> mean (10000!)! instead of the double factorial. Perhaps if everyone> put their minds to it, someone could invent a more intuitive> notation (or at the very least, not negatively intuitive). Perhaps ?> will work? Or maybe &!? I think 10000(!!) works quite well in ASCII, and FWIW I agreethat 10000!! looks like it should mean take 10000, apply the !operator, then apply it again, not take 10000, apply the !operator, then divide out all the odd-numbered factors. Soregardless of what Mathematica may think, this math student isgoing to use those parentheses [next time I have a reason towant the double factorial of anything ;] . I believe 10000? is common notation for the 10000th triangularnumber, sum(i=1 to 10000)(i). Do I remember correctly? 10000&! just looks silly. :)-Arthur=== === Subject: : Re: Fastest factorial algorithm> Actually, 10000!! is easy, using Mathematica. The !! notation> represents the double factorial function, such that n!! => n*(n-2)*(n-4)*....Just curious... what's the use of such a function? - Risto -=== === Subject: : Re: Fastest factorial algorithm>> Actually, 10000!! is easy, using Mathematica. The !! notation>> represents the double factorial function, such that n!! =>> n*(n-2)*(n-4)*....> Just curious... what's the use of such a function?A Google search turns up ,among others.-- Dave SeamanJudge Yohn's mistakes revealed in Mumia Abu-Jamal ruling.=== === Subject: : Errata for Spivak's Calculus on ManifoldsDoes anyone know if an errata exists for this text? I wan to checkbefore going through the drudgery of contacting the publisher. As faras I can tell there is no errata available on the web. Thanks inadvance.=== === Subject: : definition of UniformityHiI'm working in the study of some crystals with vacancies. Crystal arestudied like an orderen arrangement of atoms that forms a net. In one dimension this can be represen like a sequence of points at theseme distance:(i would represent the unit cell, this part of the secuence isrepetead infynit times.). . . . . . . . . . . . . . Now, if we have put some vacancies (faults of atoms) The secuence canbe. . . . . . . . . . . I want to know if there is a definition of uniformity in the folowingform:The most uniform distributions of the vacances in such a sequence iswhen the vacancies are as far as we can from each other. (There is asmal trick that the secuence is repetead so, the end and begining ofthe secuence are conec)TIAZunbeltz IzaolaUniversity of the Basque Country-- Remove XXX from email: zunbeltz@wm.lc.ehu.esXXX=== === Subject: : Re: Combinatorial proof> Show with combinatorial reasoning that> C(3n,3) = 3*C(n,3)+6n*C(n,2)+n^3, where C(n,k) is n choose k.> Am I supposed to show that both sides of the equation counts the thing? The text where you found this exercise should probably explain what they mean by combinatorial reasoning. You should attempt to use their definition. It also might help to try a simpler one:C(2n, 2) = 2*C(n, 2) + n^2> Does it qualify as combinatorial reasoning if I use combinatorial > identities or prove it by induction?In my definition of combinatorial reasoning or proof, sometimes identities or arithmetic or induction can be used, but the -main- intent is to interpret the symbols as statements about combinatorial objects (sets, subsets, tuples, trees, etc) and the manner in which they are coun. To show an equality (as above) you take one mathematical situation (most likely simply described by one side of the equation), and interpret it another way (corresponding to the other side of the equation).So I would say -first- use combinatorial ideas, and only then for small lemmas might you bother with identities/induction/arithmetic.Of course, the above identity is -very- trivial with arithmetic, just replace C(n,k) with the appropriate factorials and simplify. (No, I can't do that in my head, but I can do the combinatorics very easily in my head.) Trivial means mindlessly, just applying the rules you have without thought.> Any good hints, by the way?I will refrain from commments about the other hint ;).My hints are these:+ corresponds to disjoint union of sets.* corresponds to ...what? ... you can think of it as repea summation, or as first doing one thing, then doing another (i.e. 3*C(n,3) means do something in three possible 3 ways first, then do something taking C(n,3) ways).n choose k is not only the -number- of subsets of size k out of n.^ corresponds to ... what?... repea multiplication or tuples or functions from x to y (which is counterintuitively coun by y^x)Combinatorial reasoning just assigns meaning to the parts of the formula.MitchPS Hi 273!=== === Subject: : Re: Sex and Math Discussion, linux)> recently came up with the excellent idea of using modern> advertising techniques to get his theories through to the public. I> have decided that this is an excellent way for me to promote my> anti-Cantorian doctrine to the public. Now, it is well known that sex> sells. Therefor, without further ado (please maximize your window):Brilliant. You've convinced me that you're right, although I've beentemporarily distrac from what the question was.Also, an 11-year-old shouldn't have access to such explicit images. Ihope someone tells your momma.-- I've been thinking about my problems with getting any kind ofadmission that my math arguments showing the core error in mathematicsare correct, so I've gone to marketing books. -- James S. Harris, on when mathematics isn't enough