reaton@goodnet.com wrote: > > It has been 34 years since college for me, and I have reached a time that I can > start letting up a little in my chosen career and start looking around for some > fun things to do. While in college, my exposure to calculus was about 1 year, and > although it was a tough pull, it was fascinating and enjoyable and somewhat of > a diversion from other science courses that I took. I have always enjoyed > mathematics, math games and such and occasionally find myself thinking about > my environment in some mathematical form. I would like to go back and recapture > calculus (& analytical geometry), just for the fun of it. I've tried this a > couple of times in the last few years, but because of interruptions (read other > demands) and a lack of a good text (read difficult; does not read easily and > not a page turner) I have not succeeded. Would anyone that frequents this > newsgroup have any suggestions for me concerning appropriate texts or teaching > and learning aids. Although it has been a long time since I have had to really > use "higher mathematics," I had a good foundation in all mathematics in high school > and I have surprised myself on my recall of nearly all material up to the college > calculs level, so I'm pretty sure this is a do-able thing. > > Any suggestions would be appreciated. > > Ron Eaton > > -----------------------------------------------------------------------> This article was posted to Usenet via the Posting Service at Deja News: > http://www.dejanews.com/ [Search, Post, and Read Usenet News] This is a test from sci.mathReturn to Top
Well, this is as silly a thread as appears semi-regularly, and I can't believe I'm actually going to hit the send button for such nonsense, but then nobody's perfect. The debate all stems from the usual confusion between science and maths, as Ilias pointed out, (though not quite in so many words, perhaps alas). "Can possibly happen" appears to be scientific, (logico-observational); and "probability zero" is purely mathematical. However. Let me contribute some nonsense of my own. I hereby assert that the two phrases are IDENTICAL in meaning. It is said that there are events with probability zero, that "can happen". I hereby deny it. I claim, all events of probability zero CAN NOT HAPPEN, by definition, if you like. "But but", I hear you leaping to cry out, scrambling over one another in haste to be first with the usual alleged counter-example, gibbering and drooling on one another! (Isn't usenet *fun*!) So let me just choose one of you, and have it out. You: But what about the experiment we've just done, whereby we observed some continuous random variable, and got an observed answer? Say uniform[0,1] for definiteness. We just observed X1 = 0.341888721.... Me: (grinning diabolically) But that's a *past* experiment, and probability only applies to the *future*, doesn't it? You: (jumping up and down): Oy, hoy! That's just a fudge; surely you're not going to stand on a technicality like *that*. Me: Well I might; but anyway, there's no future event in your scene, is there? You: OK OK. We just observed X1 = 0.341888721.... and are just about to observe an i.i.d X2. Now I admit that that *particular* value won't occur again... Me: How very sweet and generous of you. You: ...but it *did* happen the first time (for X1), didn't it?" Me: No it didn't! You: What!? Me: Or rather:- just what *is* it you are claiming happened the first time? You: We got X1 = 0.341888721... ! Me: But those dot-dot-dots are the root of the problem. If you just mean we observed 0.3418887205 < X1 < 0.3418887215, then that event had a strictly positive probability of, let me see, ten to the minus, ah... You: No no NO! I didn't mean that. I meant that X1 was equal to some actual infinite sequence of decimal numbers, beginning with 0.341 etc Me: OK; but WHAT infinite sequence of decimals? You: Well, I wrote down the first several, I'm not going to bother writing down any more, I haven't got the time! Me: But I insist! You had the time to insist it was an experiment with an outcome of that form, so I insist on being told the outcome! You: Well yes, all right, all right. But I don't actually have to *tell* you surely? I mean, the outcome was there on the dial, after all. Me: But that crumby dial only told me that X1 was between 0.335 and 0.345, and that event has probability... You: Yeah yeah! But we just couldn't read it very exactly. The fully precise outcome was *there*. Me: No it wasn't. You: Yes it *was*. I set up the experiment, so I should know! Me: But all you set up was a situation where we were told that X1 was betwe-... You: Yes but now I'm using a much more precise dial-... Me: But that just means X1 will be between... You: ...that measures things to INFINITELY many decimal places. So what do you say if I told you the outcome was X1 = 0.341888721 + pi/(ten-to...) Me: I'd say you were lying, because it would never come *exactly* to that, unless you're a miracle worker and you've been cheating. Nor to any other definable number. You: Definable? Well, whatever that means is irrelevant, because it *has* come to *some* actual number, with infinitely many dec places. Me: How do you know? You: Because I can measure it with this infinite-precision dial here! Hah! Me: "Hah" to you! You know perfectly well there's no such thing. As you know from Heisenberg and information theory and all that, you can't possibly get infinite precision on a continuous measurement, can you? You: Oh well! If you're just going to fall back on a *scientific* matter... Me: Well wasn't that what I said right at the start? *You* described the experiment in those terms, scientific terms; not me. You ought to know that all continuous math models are just continuous approximations to incredibly complex discrete observations we only ever actually *make*. You: Yeah but... Oh hell! Forget the continuous dial reading then. Make it an endless sequence of coin tosses. Now:- Me: You know perfectly well that I can say all of the above exactly the same in that case. I'd still insist on knowing the exact sequence. You: But, but... Heisenberg wouldn't apply! There's no "h-bar" in the set-up this time! Me: No; but if you want to observe all those outcomes, there's quite a bit of big-G and c, isn't there! Didn't you see John Baez' latest post on- You: -Well; maybe if we made the coins smaller and smaller, and tossed them faster and fa... OK OK! No need to slobber; I take that back. Hmmm... maybe it *is* intimately involved with science rather than just math. Still, I can't help feeling there's *really* an actual outcome there, that had probability 0, and actually *did* occur. Me: You "can't help feeling" it!? Hah. Well *I* can't help feeling you're just a religious nutter in disguise, grasping at straws in a desparate attempt to find any silly & meaningless "counter-example" to what is obviously true:- events of probability zero NEVER HAPPEN. Never WILL happen, and never DID happen! You (stomping off): Mutter... stupid argument... mumble... twerp... grumble... ================================. Bill Taylor | The unrefined and sluggish mind Math Department | Of Homo Javanensis, University of Canterbury, NZ | Could only treat of things concrete W.Taylor@math.canterbury.ac.nz | And present to the senses. fax (0064-3-) 364 2587 | =============================================================================|Return to Top
|| >Have I implemented the correct algorithm? || || Yes. You may also start with u := 10, but nobody does because then || we couldn't compare results. There are other, alternative starting || values depending on the characteristics of p. Really? Cool. I have to try that out sometime... || There's quite a difference between a 31 bits and 61 bits. Plus you're || squaring -- 62 bits and 122 bits. Sounds like overflow. You have || implemented the correct algorithm incorrectly :-) Well, my code *should* be able to handle integers up to 24000 bits. Whether it actually does or not is another question. :) Well, since the algorithm is correct, it must be a problem with my code... Turbo Debugger here I come... || A P133 should take about 37 hours to test 2^1257758-1 -- the largest || known Mersenne prime weighing in at about 375K digits. || || BTW, the Lucas-Lehmer test has been ported to the PowerMac by John || Sweeney. Look for the "Free Software!" link while visiting the || above URL. John did an outstanding job. Written entirely in 'C', || the program really screams. Impressive. Well, once I get this version working and "algorithmically-optimized", I'm going to rewrite the whole thing in flat-mode assembler, optimized for the Pentium's dual pipelines. That should be a fun weekend... :) Thanks for the response, -Mike ___________________________________________________________ Michael Anttila aka PsychoMan of Craw Productions 2A Pure Math / Computer Science at U. of Waterloo, Canada E-Mail: manttila@undergrad.math.uwaterloo.ca Homepage: http://www.undergrad.math.uwaterloo.ca/~manttila/ Craw Productions: craw@magi.com, http://www.magi.com/~craw/Return to Top
dean@psy.uq.oz.au (Dean Povey) writes: > >Hmm, well there is another experiment that would allow a decision on the fate >of the SR v AD debate once and for all. Right, the obvious one: use the same magnetic spectrometer and calorimeter to measure the power in a monochromatic beam from a small van de Graaff and from a hot source of betas. Getting a monochromatic beam from a beta-decay source when working near the endpoint is going to have huge experimental uncertainties, however, due to the low flux. >This is referred to as the "New RaE experiment", Get a clue, and write Bi-210 like everyone else. Since Bi-210 has an alpha branch, you have to be very careful. A pure beta source would be preferable so you can simply avoid that kind of problem. One with a higher Q value for decay would be even better. Having sat on a PAC for three years, I can guarantee that these would be the easy suggestions. Estimates of count rate and expected errors would also be expected; I did not see those discussed on the cited web page. >I would be interested if people think this is a definitive test of both >theories. (And if there are any experimental physicists about who might be >interested in performing it). Why don't you guys get together with Carezani and do it? -- James A. CarrReturn to Top| "The half of knowledge is knowing http://www.scri.fsu.edu/~jac/ | where to find knowledge" - Anon. Supercomputer Computations Res. Inst. | Motto over the entrance to Dodd Florida State, Tallahassee FL 32306 | Hall, former library at FSCW.
In article <96111018004521718@hottips.com>, ralph.huff@hottips.com (Ralph Huff) wrote: || At what rate and at what upward angle must a golf ball leave the driver || in order to travel 200 yards before it touches the ground? How about || 300 yards by a profesional contestant who is strong enough? || Can you figure it out? I'm no physict or engineer, but it seems that there are lot more variables involved in the problem than just the rate (of what?) and the angle. In other words: No, I can't figure out. -- ,_____. ASARI Hirotsugu ) ( Graduate Student/Teaching Assistant / | Department of Mathematics ( | The University of Illinois at Urbana-Champaign | * | 1409 West Green Street \ | Urbana, IL 61801 \_ | Voice: +1.217.333.6329 Fax: +1.217.333.9576 ) / http://www.math.uiuc.edu/~asari/ \_,/ Usual disclaimers apply.Return to Top
In article <5669r7$df7@news-central.tiac.net> numtheor@tiac.net (Bob Silverman): >"gdm"Return to Topwrote: >> [...] A toy-plane flies well. I want to build a plane twice >> bigger. I thought candidly that the engine had to be 2*2*2=8 times more >> powerful. I was wrong: the engine had to be 8*root(2) more powerful [...] > > Kinetic energy of the plane is 1/2 m v^2. > What happens next depends on how you measure 'size'. If twice as > big means increasing all linear dimensions by 2, then the mass of the > plane will increase by 8 (mass is proportional to volume). > > Now ask yourself: If v must remain the same, and m increases by 8x, > what must happen to the kinetic energy? Ah, but why should v remain the same? By doubling the size, weight increases by a factor of 8, but the wing area increases only by a factor of 4, which means the wing loading (Weight/Area) has increased by a factor of 8/4 = 2. Without going into details, a higher wing loading means the margin above stall speed has decreased, or even gone negative, which violates an implied condition of the problem -- namely that the larger airplane flies as well as the smaller one. I suppose I should be careful here -- it's easy to make a bunch of implied assumptions about the airplane. For example, some airplanes are capable of hovering, in which case v does indeed stay constant, at zero. I'd go back and look at the numbers in that case, if I wasn't feeling so lazy at the moment... -- Frank Manning -- Chair, AIAA-Tucson Section
In article <5669r7$df7@news-central.tiac.net> numtheor@tiac.net (Bob Silverman): >"gdm"Return to Topwrote: >> [...] A toy-plane flies well. I want to build a plane twice >> bigger. I thought candidly that the engine had to be 2*2*2=8 times more >> powerful. I was wrong: the engine had to be 8*root(2) more powerful [...] > > Kinetic energy of the plane is 1/2 m v^2. > What happens next depends on how you measure 'size'. If twice as > big means increasing all linear dimensions by 2, then the mass of the > plane will increase by 8 (mass is proportional to volume). > > Now ask yourself: If v must remain the same, and m increases by 8x, > what must happen to the kinetic energy? Ah, but why should v remain the same? By doubling the size, weight increases by a factor of 8, but the wing area increases only by a factor of 4, which means the wing loading (Weight/Area) has increased by a factor of 8/4 = 2. Without going into details, a higher wing loading means the margin above stall speed has decreased, or even gone negative, which violates an implied condition of the problem -- namely that the larger airplane flies as well as the smaller one. I suppose I should be careful here -- it's easy to make a bunch of implied assumptions about the airplane. For example, some airplanes are capable of hovering, in which case v does indeed stay constant, at zero. I'd go back and look at the numbers in that case, if I wasn't feeling so lazy at the moment... -- Frank Manning -- Chair, AIAA-Tucson Section
Paul Turkstra <6pt@qlink.queensu.ca> wrote: >Suppose that A^3(a standard square matrix) = 0. Verify by matrix >multiplication that: > > (I-A)^-1 = I + A + A^2 > Hi ! it doesn't even matter whether A is a square matrix or an ordinary C-number: 1+A^3=(1-A)(1+A+A^2),since A^3=0 this means 1 =(1-A)(1+A+A^2).now multiply with (1-A)^-1 from the left. -> (1-A)^-1 = 1+A+A^2 ! (1, in my notation, stands for the unit square matrix, of course) greetings godzillaReturn to Top
In article <55okv5$t7t@ccshst05.cs.uoguelph.ca>, devens@uoguelph.ca (David L Evens) wrote: The idea of an empty set is quite > well defined. Yes please! I would love to see your definition of the empty set. Terry Moore, Statistics Department, Massey University, New Zealand. Imagine a person with a gift of ridicule [He might say] First that a negative quantity has no logarithm; secondly that a negative quantity has no square root; thirdly that the first non-existent is to the second as the circumference of a circle is to the diameter. Augustus de MorganReturn to Top
dylan@wam.umd.edu (Dylan Greene) writes: : : Given a convex polygon with N sides of arbitrary lengths - : does the point A, B fall inside or outside of that polygon? : : Not too hard, but here's the pusher - is there a formula for : this, or even a tight C function (better than O(N)), that can : do this? : : The method I'm using right now is horizontal line scans, : counting how many times the side of a polygon is crossed. [...] : There is a cheap (i.e. constant time, based on integer computations and positive-zero-negative testing) method of finding out if a point is to the left-of, on, or to the right-of a given directed line segment on the 2-d plane. If a point is inside a convex polygon (which is described as a sequence of vertices or edges in counter-clockwise order), then this point is always "to the left of" all of the edges of the polygon. There is no need to project rays and check boundary crossings (this is needed for non-convex polygons). If you want to know about cheaper approaches (or a proof of whether an O(N) is a necessity) let me suggest either the various comp.graphics FAQs or Joseph O'Rourke's excellent introduction to computational geometry. O'Rourke is also the one who maintains some of these FAQs, is on the net, and will probably answer questions (if you ask politely enough and have previously checked the FAQs :-). In general, if you are willing to spend O(N.lgN) time in preprocessing (i.e. doing a "sort"), you can amortize various kinds of tests into O(lgN) time by divide-and-conquer or binary search approaches. What you actually want depends on the context in which you will be using the above test. But I really recommend the FAQs. You will even find C code to do what you want. --KrishnaReturn to Top
In article <566d6k$ms8@cantuc.canterbury.ac.nz>, Bill TaylorReturn to Topwrote: @Well, this is as silly a thread as appears semi-regularly, and I can't @believe I'm actually going to hit the send button for such nonsense, but @then nobody's perfect. The debate all stems from the usual confusion @between science and maths, as Ilias pointed out, (though not quite in so @many words, perhaps alas). "Can possibly happen" appears to be scientific, @(logico-observational); and "probability zero" is purely mathematical. @ @However. @ @Let me contribute some nonsense of my own. I hereby assert that the two @phrases are IDENTICAL in meaning. It is said that there are events with @probability zero, that "can happen". I hereby deny it. I claim, all events @of probability zero CAN NOT HAPPEN, by definition, if you like. @ @"But but", I hear you leaping to cry out, scrambling over one another in @haste to be first with the usual alleged counter-example, gibbering and @drooling on one another! (Isn't usenet *fun*!) So let me just choose one @of you, and have it out. @ @ @You: But what about the experiment we've just done, whereby we observed some @ continuous random variable, and got an observed answer? Say uniform[0,1] @ for definiteness. We just observed X1 = 0.341888721.... @ @Me: (grinning diabolically) But that's a *past* experiment, and probability @ only applies to the *future*, doesn't it? @ @You: (jumping up and down): Oy, hoy! That's just a fudge; surely you're not @ going to stand on a technicality like *that*. @ @Me: Well I might; but anyway, there's no future event in your scene, is there? @ @You: OK OK. We just observed X1 = 0.341888721.... and are just about to observe @ an i.i.d X2. Now I admit that that *particular* value won't occur again... @ @Me: How very sweet and generous of you. @ @You: ...but it *did* happen the first time (for X1), didn't it?" @ @Me: No it didn't! @ @You: What!? @ @Me: Or rather:- just what *is* it you are claiming happened the first time? @ @You: We got X1 = 0.341888721... ! @ @Me: But those dot-dot-dots are the root of the problem. If you just mean we @ observed 0.3418887205 < X1 < 0.3418887215, then that event had a @ strictly positive probability of, let me see, ten to the minus, ah... @ @You: No no NO! I didn't mean that. I meant that X1 was equal to some @ actual infinite sequence of decimal numbers, beginning with 0.341 etc @ @Me: OK; but WHAT infinite sequence of decimals? @ @You: Well, I wrote down the first several, I'm not going to bother writing down @ any more, I haven't got the time! @ @Me: But I insist! You had the time to insist it was an experiment with @ an outcome of that form, so I insist on being told the outcome! @ @You: Well yes, all right, all right. But I don't actually have to *tell* @ you surely? I mean, the outcome was there on the dial, after all. @ @Me: But that crumby dial only told me that X1 was between 0.335 and 0.345, @ and that event has probability... @ @You: Yeah yeah! But we just couldn't read it very exactly. The fully @ precise outcome was *there*. @ @Me: No it wasn't. @ @You: Yes it *was*. I set up the experiment, so I should know! @ @Me: But all you set up was a situation where we were told that X1 was betwe-... @ @You: Yes but now I'm using a much more precise dial-... @ @Me: But that just means X1 will be between... @ @You: ...that measures things to INFINITELY many decimal places. So what do @ you say if I told you the outcome was X1 = 0.341888721 + pi/(ten-to...) @ @Me: I'd say you were lying, because it would never come *exactly* to that, @ unless you're a miracle worker and you've been cheating. Nor to any @ other definable number. @ @You: Definable? Well, whatever that means is irrelevant, because it *has* @ come to *some* actual number, with infinitely many dec places. @ @Me: How do you know? @ @You: Because I can measure it with this infinite-precision dial here! Hah! @ @Me: "Hah" to you! You know perfectly well there's no such thing. As you @ know from Heisenberg and information theory and all that, you can't @ possibly get infinite precision on a continuous measurement, can you? @ @You: Oh well! If you're just going to fall back on a *scientific* matter... @ @Me: Well wasn't that what I said right at the start? *You* described the @ experiment in those terms, scientific terms; not me. You ought to know @ that all continuous math models are just continuous approximations to @ incredibly complex discrete observations we only ever actually *make*. @ @You: Yeah but... Oh hell! Forget the continuous dial reading then. @ Make it an endless sequence of coin tosses. Now:- @ @Me: You know perfectly well that I can say all of the above exactly the same @ in that case. I'd still insist on knowing the exact sequence. @ @You: But, but... Heisenberg wouldn't apply! There's no "h-bar" in the @ set-up this time! @ @Me: No; but if you want to observe all those outcomes, there's quite a bit @ of big-G and c, isn't there! Didn't you see John Baez' latest post on- @ @You: -Well; maybe if we made the coins smaller and smaller, and tossed @ them faster and fa... OK OK! No need to slobber; I take that back. @ Hmmm... maybe it *is* intimately involved with science rather than @ just math. Still, I can't help feeling there's *really* an actual @ outcome there, that had probability 0, and actually *did* occur. @ @Me: You "can't help feeling" it!? Hah. Well *I* can't help feeling @ you're just a religious nutter in disguise, grasping at straws in @ a desparate attempt to find any silly & meaningless "counter-example" @ to what is obviously true:- events of probability zero NEVER HAPPEN. @ Never WILL happen, and never DID happen! @ @You (stomping off): Mutter... stupid argument... mumble... twerp... grumble... As Bill's Dialogue Concerning Two New Sciences underscores, observing an infinite sequence of Bernoulli trials (i.e. a real number) is an abstra- ction. All physical experiments and observations yield rationals; none has ever produced a non-rational real. Forget P = 0; such a thing is simply _impossible_... it cannot happen (!). Never has, and never will. If we grant this abstraction, it is math, not physics. The n-th trial takes time 1/2^n ?! Yeah, right. Infinitely many coin-flippers... march- ing off to infinity? Maybe we keep them in our vicinity by making them smaller and smaller... But even then they have a limit point! (Turing used a similar argument in his analysis of computability). We just _assume_ B^w, for B Bernoulli with p + q = 1. If 0 < p < 1 and x is in B^w, "x can not occur" is logically false. It also has pro- bability 1. So some are tempted to assert it. After all, modifying the measure at one point, or countably many, does not alter any results. Of course the fact that P({x}) = 0 for all x says very little about P; it is the values on intervals (sets of x with initial segment s) that deter- mine which P we have. For B^w it comes down to p. The remarkable part is focusing on _one_ countable set, the definable (recursive) x's, and deeming it "more justified". A little-known fact: coins have tiny cellular telephones and talk to each other; and they all have access to an oracle for zero jump as well. They will not be caught doing anything recursive, or recursively enumerable... Clever little devils. Ilias
In articleReturn to Top, Bernd Petrovitsch wrote: >"Christopher Anderson" writes: > >> While in an interview I was asked why when a value of x is placed into x^3 >> -x it is divisible by 6. Fortunately I was not asked to show this using >> algebra. However I was told to simplify it thus x(x-1)(x+1) and place >> values of x in. Assuming each term is separate we got list of numbers >[stuff deleted] >You had the solution already here (rewritten so that it is even more clear): >x^3-x = (x-1)x(x+1) >i.e. you have the product of three consecutive numbers => >therefore at least one is dividable by 2 and at least one is dividable by 3 => >the product is at least dividable by 6. q.e.d. > [...] Agreed: the author of the original post (C. Anderson) did include a proof, clarified by B. Petrovich. What may disturb a person indoctrinated by the vague school distinction between "algebra" (perhaps misunderstood as thoughtless symbol manipulation?) and unspecified "non-algebra" is that the proof by inspection "divided the problem into cases", and that is looked down upon, in favour of an unbroken chain of equations or so. In this respect, I can assure the audience that "distinguishing cases" (if done correctly) in mathematical proofs is just as legitimate as a one-shot symbol-manipulating proof, and sometimes inevitable. Having said that, I can offer two smoother proofs: (1) Observe that (x+1)*x*(x-1)/(3*2*1) is "(x+1) choose 3", the number of three-member subsets of an (x+1)-member set. Hence x^3 - x = ((x+1) choose 3) * 6. Fertig. (2) Denote a(x) = x^3-x. Then a(0)=0, a(1)=0, both divisible by 6, and then we check mechanically that a(x+2) = 2 * a(x+1) - a(x) + 6 * (x+1) so that the result follows by mathematical induction. Have fun, ZVK (Slavek).
In article <32857B1C.73EB@pl.jaring.my>, Tang Chi YanReturn to Topwrote: [...] >Anyone there knows how to do this? > > |\ > | x^2 > | -------- dx > \| x^4 + 1 [...] Let s be a symbol for sqrt(2), then x^4 + 1 = (x^2 + 1)^2 - 2 * x^2 = (x^2 - s * x + 1)*(x^2 + s * x + 1) and then you apply standard partial fractions procedure (it is still a lot of symbol manipulation, but routine). Good luck, ZVK (Slavek).
Let C be Cantor set. can you find a subset D of R that is omeomorph with C, and such that Lebesgue measure of D isn' t zero?Return to Top
ksbrown@seanet.com (Kevin Brown) wrote: >So here are the smallest null sums for 1st through 5th >powers: > 1+2-3 = 0 > 1+4-9+16-25-36+49 = 0 > 1+8-27+64-125-216-343+512+729-1000-1331+2744 = 0 ^^^^ You mean 1728, of course. > 1^4 + 2^4 + 3^4 + 4^4 - 5^4 - 6^4 - 7^4 + 8^4 + 9^4 + > + 10^4 + 11^4 + 12^4 - 13^4 - 14^4 - 15^4 + 16^4 = 0 > 1^5 + 2^5 - 3^5 - 4^5 + 5^5 + 6^5 - 7^5 - 8^5 - 9^5 > + 10^5 - 11^5 - 12^5 - 13^5 + 14^5 + 15^5 + 16^5 - 17^5 > + 18^5 + 19^5 + 20^5 - 21^5 - 22^5 - 23^5 + 24^5 = 0 >Letting f(n) denote the least integer k such that at least one signed >sum of the first k nth powers equals zero, we have f(0)=0, f(1)=3, >f(2)=7, f(3)=12, f(4)=16, and f(5)=24. What is f(6)? Here are some additional results, in a more compact form: S is a subset of {1, 2, ... , f(n)} the nth powers of which have the same sum as the nth powers of its complement. [Note that my solution for n=5 differs from yours.] n f(n) S 1 3 {3} 2 7 {3, 5, 6} 3 12 {1, 2, 4, 8, 9, 12} 4 16 {5, 6, 7, 13, 14, 15} 5 24 {3, 4, 6, 8, 9, 11, 12, 16, 17, 18, 22, 24} 6 31 {1, 6, 7, 8, 11, 15, 18, 21, 24, 27, 29, 31} 7 39 {2, 4, 5, 7, 8, 11, 12, 13, 15, 22, 23, 24, 29, 31, 32, 35, 36, 39} 8 47 {1, 2, 3, 8, 10, 13, 14, 15, 16, 17, 18, 25, 29, 31, 32, 33, 36, 38, 39, 40, 42, 43, 47} 9 44 {3, 5, 9, 10, 14, 19, 20, 21, 25, 26, 28, 31, 35, 36, 37, 38, 40, 41, 42} 10 60 {2, 3, 4, 11, 13, 14, 17, 24, 25, 26, 32, 35, 38, 39, 41, 42, 43, 46, 48, 49, 58, 59, 60} So f(n) isn't monotonic; but its growth appears to be roughly quadratic. -- Fred W. HeleniusReturn to Top
I'm taking a course in category theory, and the term 'natural bijection' often pops up. But I can't seem to find a nice definition of what is meant with the phrase. Let's say we've got two categories, C and D, with a bijection (*not* a functor, just bijection) F between the arrows/morphisms of the two categories. Then the idea of the 'naturalness' seems to mean that the bijection (much like a functor) preserves the identity of the arrows under arrow-composition. More formally, (the way I understand it, in any way!) for p: X1-->Y, q: X2 --> Y arrows in C, that is we've got the diagram p q X1------> X2 --------> Y the 'naturalness' of F means that F( q o p ) = F( q ) o F( p ) for all arrows p and q in C. (where the notation F(p), for p an arrow in D, refers to the arrow in D that is associated with p under the bijection F) But this only makes sense when there is a 'total' (don't know the proper term bijection F associating *all* the arrows in C with arrows in D (and of course visa vers). What if there is only a subsection (also not a formal term) of the arrows in C that is bijected with a subsection of the arrows in D? For example, what if we've got the following: For X a specific object in category C and W a specific object in category D, let F be a bijection mapping arrows (in C) to X to arrows (in D) to W. Now what is meant with the phrase 'let F be 'natural bijection in X' ? What bothers me is that the bijection is only defined on arrows with X and W as codomains (in C and D respectively), so the above definition is not really of much use. I have an idea that the 'naturalness' of a bijection is only of relevance when one also has a functor defined from C to D, and that it has got something to do with the interactions between the mappings of the bijection and the mappings of the functor. Thanks a lot for any tips. Judy Retief judy.retief@epiuse.co.zaReturn to Top
Ralph Huff wrote: > > At what rate and at what upward angle must a golf ball leave the driver > in order to travel 200 yards before it touches the ground? How about > 300 yards by a profesional contestant who is strong enough? > Can you figure it out? This is somewhat of an easy solution. Disregarding you're normal mathematical concepts, and looking at the question as being more physics related, there are two angles that will give you the same displacement in the x-direction. This displacement is given by the equation: Dx = [(v0)^2*sin2@]/g ThereFORE ;), substituting the given distances of both 200 and 300 yards separately into the afore mentioned equation, and using an arbitrary angle, of say 30 degrees (which is a good approximation for a regular drive): The 200 yard drive would require having an initial velocity of 47.5732 m/s at an angle of 30 degrees to the horizontal. The 300 yard drive would require having an initial veloctiy of 58.2651 m/s at an angle of 30 degrees to the horizontal. However, there are numerous solutions that entail different angles to the horizontal which thus change the required velocity. Thus, it can be concluded that the required component of velocity is dependent on the angle that the ball is driven to the horizontal axis. Hope this answer is sufficient!!! P.TReturn to Top
Greetings, John. I believe your sum of squares sequence is an integer at least up to denominator 19. Don. : From: mckay@cs.concordia.ca (MCKAY john) : Newsgroups: sci.math : Subject: Re: Law of small numbers [ Sequence problem.] : Date: 25 Oct 1996 08:58:28 GMT : Organizn: Computer Science, Concordia University, Montreal, Quebec : Message-ID: <54pvfk$1co@newsflash.concordia.ca> : : a[0]:=1;a[1]:=1; for n>=1, a[n+1]:=sum(a[k]^2,k=0..n)/n : What is the smallest value of a[n] not an integer? ... #Don. 1, 1, 2/1, 6/2, 15/3, 40/4, 140/5, 924/6, 24640/7, ?, ? -- REM 5*11*13 *128 *829*3527 = 2.67593772E11 rem > .smallnos.block1 Prog "donmcd.calc.profile.smallnos.anann/n2", 8.11.96, 20:40 pm. multiprecision Integer multiply/divide, SEQUENCE.. (mean sum of squares..) ##################### an*(an+n)/(n+1) = 2*(2+1)/2, 3*(3+2)/3, 5*(5+3)/4 , ... 678e5319 /18 = integer 1e10641 /19 = 074,767,494,499, .. = integer.** REM FOR count = 1 TO 16.. cont. SEQUENCE. ***** 6e0 /2 cofactor = 003, remainder 0 **** 15e0 /3 cofactor = 005, remainder 0 *** 40e0 /4 cofactor = 010, remainder 0 140e0 /5 cofactor = 028, remainder 0 924e0 /6 cofactor = 154, remainder 0 24e3 /7 cofactor = 003,520, remainder 0 **24,000+ 12e6 /8 cofactor = 001,551,880, remainder 0 **12,000,000+. 2e12 /9 cofactor = 000,267,593,772,160,/cont. / remainder 0 ********************** shown by previous email. 71e21 /10 cofactor = 007,160,642,690,122,/cont. / 633,501,504, remainder 0 51e42 /11 cofactor = 004,661,345,794,146,/cont. / 064,133,843,098,964,919,305,264,116,096, remainder 0 21e84 /12 cofactor = 001,810,678,717,716,/cont. / 933,442,325,741,630,275,004,084,414,865,420,898,591,223, 522,682,022,447,438,928,019,172,629,856, remainder 0 3e168 /13 cofactor = 000,252,196,724,522,/cont. / 541,410,812,579,097,160,361,769,690,288,016,260,160,445,329, 059,280,814,119,090,545,214,689,630,356,941,057,966,683,002,706, 243,045,823,080,829,174,307,488,383,892,818,892,448,294,858,132, 739,063,481,087,616, remainder 0 63e333 /14 cofactor = 004,543,084,847,135,/cont. / 617,156,827,912,757,388,745,495,368,280,304,614,840,838,595, 881,866,184,916,862,484,568,611,323,251,237,466,514,400,298,666, 035,505,442,921,252,351,741,476,408,723,848,134,651,603,051,301, 482,732,426,317,279,967,824,692,473,590,004,311,667,893,669,816, 825,659,451,437,945,264,179,017,683,087,851,534,875,769,612,520, 430,358,764,794,779,896,148,056,440,854,180,983,745,517,181,150, 456,925,894,414,444,744,263,895,766,823,050,176, remainder 0 20e666 /15 cofactor = 001,375,974,661,884,/cont. / 883,593,958,307,872,179,178,705,368,405,647,167,653,708,277, 552,968,028,912,473,812,609,102,217,376,850,169,111,765,710,515, 773,835,599,302,526,014,250,241,161,260,301,717,399,820,768,970, 184,134,876,804,192,150,886,854,801,356,030,366,186,182,424,436, 442,996,889,021,994,405,615,153,205,582,903,467,344,478,792,123, 106,618,114,102,235,565,032,186,504,968,849,726,350,885,599,336, 533,205,922,352,410,334,758,695,941,004,389,844,907,248,384,651, 429,484,082,872,799,202,174,077,593,625,353,904,681,667,598,612, 880,451,668,712,691,329,300,699,545,740,348,437,987,114,107,645, 533,752,280,969,067,680,573,611,264,214,603,078,561,454,961,628, 228,293,064,187,407,527,797,705,091,082,562,348,153,851,826,709, 309,999,245,224,806,527,712,609,283,567,103,740,647,842,272,786, 590,546,895,644,500,236,443,431,510,130,695,525,780,542,823,497, 682,908,835,486,798,511,724,130,649,088,896, remainder 0 1e1332 /16 cofactor = 000,118,331,641,884,/lines deleted cont. / 068,353,612,205,856,207,165,427,016, remainder 0 14e2661 /17 ** 14.,,,, x 10^2661 / 17. ## equals INTEGER. cofactor = 000,823,669,263,002,/cont. lines deleted/ 708,015,852,736, remainder 0 Product is quite big. # I did not multiply any more. ### In this program. Except by modulo arithmetic. In program anann/n1, I multiplied as ## far as denominator = 19. ## I looked to see if the next factor 18, 19, 20, ..., was (hopefully going to come up in time) spare.# 18 cofactor = 000,045,759,403,500,/cont. lines deleted/ 706,000,880,707, remainder 10 count =17, n2 = 10*27 = 0 MOD (n1) Prospective = 18 cont. 10*(10+17) ***************** i.e. remainder*(remainder + 17 ) MOD (count +1) =? 0 ========================================================= Denominator 18 is going to be o.k.# Verified by multiply not shown here. 19 cofactor = 000,043,351,013,842,/cont. lines deleted / 721,474,518,565, remainder 1 count =18, n2 = 1*19xxxx = 0,MOD (n1) Prospective = 19 cont. ****************** Factor 19 is going to be o.k. to divide evenly !##? NO! NO! Should be 1*(1+17) MOD 19.. <> 0 xx However Proved by multiply, not shown = 1.,,x 10 ^10641 / 19 = INTEGER. ********************** don.mcdonald@welcom.gen.nzReturn to Top
darla@accessone.com (Darla) writes: > You cannot judge the importance or the value of a thing by the number and > weight of the tools needed to produce or complete it. It takes a lot of > heavy equipment to haul garbage, but only a heart to fall in love. And > which is the greater endeavor? Which has more directly enhanced the lives > of men and the survival of the planet? Well, how long do you think you'll continue to love if your love refuses to take the garbage away? And how long do you think you are going to *live* if the garbage keeps piling up in your rooms? Can be pretty unhealthy. -- David Kastrup Phone: +49-234-700-5570 Email: dak@neuroinformatik.ruhr-uni-bochum.de Fax: +49-234-709-4209 Institut fuer Neuroinformatik, Universitaetsstr. 150, 44780 Bochum, GermanyReturn to Top
numtheor@tiac.net (Bob Silverman) writes: > lv54308@ltec.net (Lyle VonSpreckelsen) wrote: > > >Three Pipes supply an oil storage tank. The tank can be filled by > >pipes A and B running for 10 hours, by pipes B and C running for 15 > >hours, or by pipes A and C running for 20 hours. How long does it > >take to fill the tank if all three pipes run? > > I will give a hint: > > Think "harmonic mean". I'll offer you half of that. -- David Kastrup Phone: +49-234-700-5570 Email: dak@neuroinformatik.ruhr-uni-bochum.de Fax: +49-234-709-4209 Institut fuer Neuroinformatik, Universitaetsstr. 150, 44780 Bochum, GermanyReturn to Top
Nick Halloway (snowe@rain.org) wrote: : : This brought up the question: are there some conditions on homology : groups for a space such that a fixed point theorem holds? If a : space is contractible, does a fixed point theorem hold, i.e. : for f continuous: X --> X, does X have a fixed point? : No. Take X:=]0,1[ = {x\in R | 0Return to TopX, x |---> x^2. d.A.
eun woo park (ewpark@undergrad.math.uwaterloo.ca) wrote: : What is the difference between two concept other than the definition ? : Closedness is a topological property, openness is a metric one. : Can we have a set that is complete but not closed ? A complete subset of a metric space is necessarily a closed subset, containing as it does, its derived set. : : Can we have a set that is closed but not complet ? Yes. Take the rational numbers as your metric space (with the usual metric) and it is closed but not complete as a subset of itself. : : Is closed set in complet set complete ? Yes. The complete subsets of a complete metric space are precisely the closed subsets. : : Is complete set in closed set closed ? : Yes d.A.Return to Top
"goldbach"Return to Topwrites: > Religion does not even require the assumption of a god. Religion is > distinguished by the concept of faith which is the acceptance of > a belief without reason to do so. It is the believing ' in ' something > being true as opposed to believing ' that ' something is true. The > latter points to some kind of reason. > Religion can rot your whole life if you let it get a hold on you. Yes, it might keep you awake at night after you killed some stupid neighbour of yours. -- David Kastrup Phone: +49-234-700-5570 Email: dak@neuroinformatik.ruhr-uni-bochum.de Fax: +49-234-709-4209 Institut fuer Neuroinformatik, Universitaetsstr. 150, 44780 Bochum, Germany
>: First, I recently posted a disclaimer to two of my earlier postings, >@> but now I want to disclaim the disclaimer. :-) Someone had posted >@> saying that const qualification (in C) does not convey non-alias >@> information, because the const qualifier guarantees only that no >@> attempt will be made to write to the underlying addresses *through the >@> const-qualified pointer*. C9X, the revision of the C language that we (the C standards committee) hope to have done by year end 1999, has added a new type qualifier: restrict. It applies to pointers and indicates that there are no aliases to the pointed at object (unless the programmer gives up that property by doing an assignment of the restricted pointer to another pointer). In effect, a restricted pointer acts like a pointer to malloc'ed memory. A good place to use restricted pointers is the parameters to a function. The compiler vendors who have already implemented this new feature report great performance improvements. Fred Tydeman +49 (7031) 288-964 Tydeman Consulting Meisenweg 20 tydeman@tybor.com Programming, testing, C/C++ training D-71032 Boeblingen Voting member of X3J11 (ANSI "C") Germany Sample FPCE tests: ftp://ftp.netcom.com/pub/ty/tydemanReturn to Top
Hi, Does anybody know what should be the constraint to force a bivariate implicit polynomial to be closed (bounded) ? (e.g. x^2+y^2-25=0 is a closed one since it represents a circle). Thanx...Return to Top
Does 0.99... equal 1? I should think so, but can anyone confirm this? DieterReturn to Top
jday@csihq.com (John Day) wrote: >Can anyone recall why (in Abstract Algebra) the compositions of mappings >of sets into their permutations are called "symmetric" groups? Since each >element of the group is a permutation, why not call it a permutation group? We say a function F(x_1, ..., x_n) is symmetric if we have f(x_1, .. , x_n)=f(x_1s, ..., x_ns) for all permutations s. The "symmetric" (like "alternating" in the corresponding case) has become detached from the functions and attached to the group of all the transformations which preseerve this "symmetry". So it's not ulike what the grammarians call "transferred epithet". But Rule 0 of mathematics is "don't think the name is the definition". ******************************************************** * Dr W B Stewart phone +44 1865 279628 * * Exeter College fax +44 1865 279630 * * Oxford * * OX1 3DP * * UK home 60629 * ********************************************************Return to Top
"Jack W. Crenshaw"Return to Topwrote: >Here's what I have so far, mathematically. If the resistor connects two >_INTERNAL_ nodes (neither at power or ground), the solution resolves into >finding the determinant of the matrix: > > [ a+z -z ] > [ -z b+z other stuff ] > P = [ ... ] > [ other stuff ] > [ ] > >where z = 1/R. The matrix is symmetric, with the off-diagonal elements >The question is, what's the determinant of the matrix? From the presence >of z in the four terms shown, it would seem that we could get quadratics >in z. However, each time I try it with an example, I find the >determinant is only linear in z, which would prove my conjecture. >Somehow, the z^2 terms are cancelling. > You can see what you are asserting is true if you perform the Laplace expansion of the determinant in terms of the first two rows; you know, the sum of all the 2x2 cofactors from the top two rows times the corresponding (n-2)x(n-2) cofactor. [see any ancient book on determinants, such as Aitken's Determinants and Matrices. ******************************************************** * Dr W B Stewart phone +44 1865 279628 * * Exeter College fax +44 1865 279630 * * Oxford * * OX1 3DP * * UK home 60629 * ********************************************************
(Ilias wrote: ...) very interesting comments, for instance about "Henkin witnesses", "Skolem functions" and the "Herbrand expansion", thanks. Meanwhile I wonder how to `format' those posts - anybody still with us? At least I see that the algorithm I posted earlier was flawed in not relating the constructed names in Def( S ) to each other properly (they were all equivalent). So I `just' post it again - corrected (sorry for this `dragging game' :), but without having done a lot of reading (sorry again). Nevertheless, trying to address the given and `anticipated' comments: > By the way, this model will not necessarily be recursive... or even > recursively enumerable. And of course this only works if S is consistent > to begin with! Where >>in the given algorithm<< is something (I suppose the maps/selections or instanciations) not recursively enumerable - >>except<<, of course, `you' having to provide `your list of acceptable names' and `criteria of acceptibility' to the algorithm? > The problem is that you cannot tell > whether Ex Ay Ez R(x, y, z) holds or not if you only have some designa- > tion for x; you need the entire universe U that x, y, z range over, and > some relation R_U(.,.,.) (i.e. subset of U x U x U) to interpret the re- > lation symbol R. There might be many such ; there might be none. I'm sure that I don't understand fully what this implies, however: That's what pointed me to the `correction' - to instanciate U using all `names' already accepted in Def( S ) and to `construct' new ones enforcing consistency by check - accept or discard. Of course S and the `universe of theorems' U it `creates' remain the same throughout. Algorithm (to construct Def( S ) from a universe U( S ). (Z denotes sets): 0) Identify `initial operation axioms' - having one All-quant. or ~Ex. For P those are: Succ( x ), Add_0( x ), Mul_0( x ). From them collect the `constructive non-tautologies' in Z_C, for P this would be {Succ( x )}. 1) Select `initial number-names' Z_Ni (not necessarily distinct) and a bijective map to all i elements of Z_C (both the argument and the `result'). 2) Form the `initially instanciated universe of S' IUi replacing the free variables of All-quant.s in U( S ) successively with Z_Ni-elements in all possible ways, producing the sequence U( S ), IUi( 1 ), ..., IUi( i ) = IUi (please, read on :) 3) Check for `typographical inacceptabilities' in IU e.q. for an expression "A = B" and an expression stating that A <> B resp. ~Ex | "A( x ) = B( x )" or any (of a rec. enum. set of) absurdities. In case try another selection (1) resp. (5) with `more different names', otherwise Def( S ) = Z_N 4) Identify more `generating operations or constructive non-tautologies' from the IUk( k ) resp. IUk( k - 1). Those are expressions of the form: Ex O_yz( x ), or Ax ~O_yz( x ) where O_yz is an `symbolic operation' with argument x (or several, in case of Eu...Ex O_yz( x )) and instanciated variable(s) y (, z). Include new distinct ones in Z_C. 5) Select `number-names' Z_Nk (not necessarily distinct) and a bijective map to all k elements of Z_C (both the argument(s) and the `result', where applicable). 6) Form the `instanciated universe of S' IUk replacing the free variables of All-quant.s in U( S ) successively with Def( S ) elements in all possible ways, producing the sequence U( S ), IUk( 1 ), ..., IUk( k ) = IUk - and continue 3) - 6) (please, read on :) Comments: Definitly, 3), 4) and 6) are `critical' wrt. the `size of the entities in question', however they are part of an iterative algorithm which should have no problem to start. The `technique of number-generating operations' is (obviously) modelled after the Peano Axioms (for which I have a reference :), but it seems powerfull. The `typographical' check to decide consistency also relies on rec. enum. criteria. Thanks again for your continuing interest, Frank W ~@) RReturn to Top
Posit a truly random expansion of integers infinitely to the left and right of (for instance) a decimal point. Remove the decimal point. Now posit a second such expansion also truly random. The Polaner hypothesis states that these two infinite random expansions are identical! Reasoning that either must contain the other to any size without limit by the very definition of randomness. Is this true? Has any one any clear pop of this? The Polaner hypothesis states that there is only one infinite random expansion so expressed. That in some sense one defines the other. I get dizzy thinking about it.Return to Top
In article <5672s1$8tj@news.ox.ac.uk> Brian StewartReturn to Topwrites: >From: Brian Stewart >Subject: Re: Where's the symmetry? >Date: 11 Nov 1996 11:32:17 GMT >jday@csihq.com (John Day) wrote: >>Can anyone recall why (in Abstract Algebra) the compositions of mappings >>of sets into their permutations are called "symmetric" groups? Since each >>element of the group is a permutation, why not call it a permutation group? >We say a function F(x_1, ..., x_n) is symmetric if we have >f(x_1, .. , x_n)=f(x_1s, ..., x_ns) for all permutations s. >The "symmetric" (like "alternating" in the corresponding case) has become >detached from the functions and attached to the group of all the >transformations which preseerve this "symmetry". So it's not ulike what >the grammarians call "transferred epithet". >But Rule 0 of mathematics is "don't think the name is the definition". >******************************************************** >* Dr W B Stewart phone +44 1865 279628 * >* Exeter College fax +44 1865 279630 * >* Oxford * >* OX1 3DP * >* UK home 60629 * >******************************************************** Probably the group of a l l permutations on n objects is called the symmetric group because a function of these objects is symmetric exactly if it is invariant under a l l permutations, that is, invariant under the symmetric group. For example, the determinant of n vectors is not a symmetric function because it changes its sign under an odd permutation. It is, however, invariant under the group of all even permutations, also known as the alternating group. Quite consistently, the determinant of n vectors is called an alternating function of these vectors. There are many permutation groups different from the symmetric groups; in fact, all subgroups os symmetric groups are permutation groups. So there is a definite difference between the two concepts.
In article <3284C8AB.71C8@cdf.toronto.edu>, Peter KanareitsevReturn to Topwrites: > Does anyone know of a real-world situation where a tensor product of > vector spaces occurs "naturally" (apart from quantum mechanics)? Thanks. Any time you build a multidimensional functional space out of one dimensional ones. Surface fitting is a common one; many 2D spline spaces are tensor products of 1D spline spaces, for example. --------------------------------------------------------------------------- Tim Hollebeek | Disclaimer :=> Everything above is a true statement, Electron Psychologist | for sufficiently false values of true. Princeton University | email: tim@wfn-shop.princeton.edu ----------------------| http://wfn-shop.princeton.edu/~tim (NEW! IMPROVED!)
In article <328778BC.6657@math.unifi.it> Biblioteca matematicaReturn to Topwrites: >From: Biblioteca matematica >Subject: measure >Date: Mon, 11 Nov 1996 11:04:28 -0800 >Let C be Cantor set. >can you find a subset D of R that is omeomorph with C, and such that >Lebesgue measure of D isn' t zero? From: flor@email.kfunigraz.ac.at (Peter Flor) Subject: Re: measure Date: Mon, 11 Nov 1996 09:24:00 LOCAL Keywords: Cantor sets Of course you can, and that�s well known. The Cantor set is constructed by removing "middle thirds" infinitely often, and the resulting set has measure zero because (1-1/3)*(1-1/3)*... = 0. All you have to change is this infinite product; replace it by one that converges (i.e. to some positive number).
Thank youReturn to Top
Kralor (ms-drake@students.uiuc.edu) wrote: : Please try not to bruise me...I'm just a naive college student who's : curious. I recently started reading about set theory and all the : contrivances that are used to eliminate paradoxes such as Russell's. I : was just wondering if the entire situation could be resolved by an axiom : which doesn't allow sets to be members of themselves, or does this lead : to other problems? Thanks for any help-- If you would not allow sets to be elements of sets, the power set of a given set wouldn't be a set. Still further and because of that, you could not form e.g. the cartesian product of two sets A and B (which is a subset of the power set of the power set of AUB),... I hope this is of some help. Franka M.BruecklerReturn to Top
In article <55v90f$etp@rzsun02.rrz.uni-hamburg.de> fc3a501@AMRISC04.math.uni-hamburg.de (Hauke Reddmann) writes: > Anyone interested in p-adics may try the American > Mathematican Monthly (Aug-Sep 1996) for a nice > article on the theme. > (I would have taken this into email - if Pu's > email account hadn't been mailbombed into oblivion) Thanks, read that article. The preamble reads: " You can sum some of the series some of the time and some of the series none of the time... but can you sum some of the series all of the time?" Mathematicians up to the day of this writing still think the Naturals = Finite Integers is precise and is mathematics. That system of belief would be analogous in physics if all physicists believed that Newtonian Mechanics was modern day physics. Naturals = Infinite Integers = p-adics is the truth just as modern physics is based on Quantum Mechanics, not the older and imprecise Newtonian Mechanics. Trouble with mathematics is that the community is far lazier than is the physics community. Those guys can ignore and keep doing wrong things. Whereas in physics, experiments prompt change and prod that community into action. What is nice about the day when p-adics are found essential in physics is that mathematics will then be linked to science experiments, just as the physicists are linked to every physics experimental result.Return to Top
T.Moore@massey.ac.nz (Terry Moore) writes: > In article <55okv5$t7t@ccshst05.cs.uoguelph.ca>, devens@uoguelph.ca (David > L Evens) wrote: > The idea of an empty set is quite > > well defined. > > Yes please! I would love to see your definition of the empty set. Doubtless. But he only stated the *idea* of an empty set is quite well-defined, not the empty set itself. Now the idea of an empty set is defined as the idea of a set full of useful things I had in mind when doing this post. I have no idea whether other definitions might apply as well. -- David Kastrup Phone: +49-234-700-5570 Email: dak@neuroinformatik.ruhr-uni-bochum.de Fax: +49-234-709-4209 Institut fuer Neuroinformatik, Universitaetsstr. 150, 44780 Bochum, GermanyReturn to Top
From svk@neva.ru Sun Nov 10 16:03:45 1996 From: Sergey KhruschevReturn to TopA REPORT FROM GENERAL MEETING OF DEPARTMENT OF MATHEMATICS OF RUSSIAN ACADEMY OF SCIENCES (October 31, 1996) SERGEI KHRUSHCHEV The meeting has been chaired by Voevodin - a Buro member. First Faddeev presented his account for 5 years. When Faddeev finished I was given a word. Below is a summary of what I said. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> A SUMMARY OF THE TALK Sergei Khrushchev The decisions of Buro which I complained included: 1) Approval of USTAV of UCHREZHDENIE POMI shortly after the illegal decision on stopping my membership in Buro; 2) Publication of the announcement in "POISK" on the elections of Director of UCHREZHDENIE POMI with unlimitted rights on undetermined term from ONE CANDIDATE chosen by BURO headed by Faddeev; 3) Approval of financing unnecessary expenses of POMI from the budget of the Department; 4) Inactivity of Buro concerning financial violations in POMI discovered by authorized organizations. The main reason of my disagreement with Buro was different understanding of the aimes of our Department. >From my may be too patriotic point of view international scientific programs in Russia are important for russian mathematics and should be run effectively with economy of budget money. >From the point of view of academic-secretary (= L.D.Faddeev) it is better to work abroad and budget money of Department should be used for this very goal. Probably because of this approach round 40 of my colleagues left POMI and got work in different countries, beeing left in the POMI staff however. In addition a group of round 30 people headed by academic-secretary spends abroad approximately 70-80% of time. On a recent meeting in Smolnyi (City Administration in St.Petersburg) an official representative of Elzyn in St.Petersburg (former mathematician Sergei Cyplyaev) said to the audience of heads and professors of St.Petersburg Universities that almost all leading mathematicians left POMI. Long beeing abroad led Faddeev to complete loss of the feeling of economical reality which is so important for surviving in modern Russia. This is also the main reason for leaving by Faddeev the Justice Space of Russia. I am not going to discuss illegal orders of former Director of liquidated Euler Institute. All of them are complained by me to the court and I believe that the justice will be finally restored. The subject of my present talk is rather ordinary for our time but is not so usual for academic community, since it leaves the field of academic activity. I will talk on juridical aspects of activity of our academic-secretary. It is already known that on September 19, 1996 the court abolished the decision of Buro to stop my membership. This not so important event however well illustrates the juridical competence of our academic-secretary. Unfortunately violations of Laws may lead him to more serious consequences. Let me recall that after taking the decision on reorganization of St.Petersburg scientific institutions many documents were issued by Presidium of RAS. They finally led to adoption by Department of Mathematics and by Presidium of a "new edition" of USTAV of UCHREZHDENIE RAS "St.Petersburg Division of V.A.Steklov Institute" (such a combersome name was chosen for POMI). I present only few, the most odious, statements from this document. 1. Uchrezhdenie is created in correspondence with permission of the Council of People Komissars on January 4, 1940. 2. Uchrezhdenie has a right for external economic activity in correspondence with its requirements. 3. The property of Uchrezhdenie is in the disposal of its Director who appoints a REVISION COMMITTEE and determins the way it must work. Soon after approval of this Ustav a new Uchrezhdenie had been charged by the Main Treasury Office of St.Petersburg on the sum equal to $3000 for using budget money in wrong way. Notice that this charge equals to the sum of charges of all other checked academic organizations in St.Petersburg (round 30). Soon after completion in September of the elections announced by Buro in June of Director POMI from one candidate this very Uchrezhdenie was visited by Taxes Police of St.Petersburg. Taxes Police found at the Payroll Office of POMI several thousands of US dollars. Since POMI is not a currency exchange office the limit of the cash register is set to be zero. Whatever exceedes the limit is a subject of confiscation and of a charge. The charge for such a violation of the currency regulations is set to be 1000% of the sum discovered. Even other violations will not be found the charge amounts several dozens of thousands of US dollars. In addition to the illegal financial activity POMI exploits a palace on Pesochnaya quay, were the liquidated Euler Institute previously was located, by making use of the economical methods of Brezhev's time. It is enough to say that expences on the complex increased 2.5 times and now are beeing covered from the salaries of scientists of POMI and MIRAN. However even these expenses are not enough and debts on communal payment reached 200 million rubles (= $40 000) for the SUMMER PERIOD. I think that for actual staff of at most 40 people these are very big expences. Nobody will cover them on the regular basis and this results in arbitration court consideration. Naturally all these events couldn't not affect international programs. To begin with from 15 days they shortened up to 3-7. Next the number of participants decreased tremendously. If in 1992-94 the Euler Institute with its small staff accepted 300 foreign and 400 russian mathematicians then in 1995-96 POMI decreased this ammount approximately 10 times. At the present time POMI runs conferences by hiring commercial organizations and pays extra commission which only increases the expences. I should also mention a very important point. On the last meeting of Presidium of RAS Ustav of Uchrezhdenie was cancelled as not corresponding to Ustav of RAS. However it became clear that up to the last moment POMI was considered in USTAV of MIRAN as its part. I consulted with lawyers and they told me that any organization which wants to get its money from POMI by using this fact may take MIRAN to solidary responsibility. Notice please that now we are already talking about the sum which approaches one half of billion of rubles (=$100 000). Academic-secretary is a serious mathematician who is an author of more than 200 scientific papers and have many awards. Cooperation with him was fruitful for dozens of mathematicians who became his co-authors. But his activity in the oprganization field turned out to be ruinous for the Department of Mathematics. To conclude : To-day in the time of the market economy you actually make choice not between a candidate with heavy financial violations of the Law and other candidates but between a financial crash of Department of Mathematics and its relatively save existence. Please take notice of this alternative. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> At the end I handled a copy of my talk to the Chairman (Voevodin) and said that I can defend every word of my talk at the court if academic-secretary would make such a complain. After that another copy was given to Faddeev. After my talk first vice-president A.Gonchar took a word and confirmed that many things I talked about are correct. He told to the meeting that USTAV of UCHREZHDENIE POMI was discussed on the last Presidium of RAS in the presence of Deputy of State Duma Sergei Popov who is a member of DUMA COMMITTEE on Laws and Justice reform. Sergei Popov described to Presidium of RAS negative outcomes of this USTAV. Next Victor Maslov took a word and said that all these financial and juridical violations are not important because Faddeev is an outstanding mathematician and he obtained many important results during last years which Maslov beeing an expert in the field can confirm as such. He added that Faddeev is not guilty. This is a result of activity of Faddeev's deputies and advisors. He also said that now Faddeev was getting better in administration because he learns how to do this. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> AN IMPORTANT REMARK The idea of innocent Faddeev and bad deputies is already dead. For example, deputy of Faddeev on organization questions in Buro is Alexei Zizchenko. He is responsible for all documents Buro prepares. In particular he is responsible for USTAV which not only was approved by Buro but also was approved by a special order of Presidium signed by vice-president of RAS Andreev. Zizchenko was deputy of the following academic-secretaries: I.M.Vinogradov, N.N.Bogolubov, A.A.Gonchar, L.D.Faddeev. This list shows that he is an extremly competent administrator. He will never do things without consent of his chief. Moreover he always shows the chief possible poor results of wrong decisions. However if a chief insists he will do what he is told. So it was unfair from the side of Maslov to put the responsibility from the shoulders of Faddeev to the shoulders of Zizchenko. On the last Buro meeting where I could participate only by the decision of the court Faddeev blamed for this USTAV Anatolii Oskolkov who died last fall. This claim of Faddeev is another lie. Oskolkov also never made a step without Faddeev's consent. Moreover Oskolkov died before this USTAV was approved by Buro and Presidium. Next, financial violations are the results of activity in the Payroll Office of POMI of the former software engineer who at the age of 60-ies replaced last summer, following the directions of Faddeev, a professional bookkeeper with higher financial education who worked in POMI for many years. Obviously this devoted to Faddeev software engineer and unexperienced bookkeeper would never dare to make a step without Faddeev's consent. I cannot also agree with Maslov that Faddeev is getting better in administration. Just to the contrary I would say that violations of the Laws he makes are getting only stronger. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Buro didn't want to discuss the facts presented in my talk. Therefore Voevodin claimed that there is a very important topic to discuss. He said that Buro stopped my membership last fall. However after my complain to the court this decision was cancelled. Now the Department of Mathematics may be charged 30 million rubles (= $6000) for moral demage made by this decision of Buro to Khrushchev. He told that Buro member Ildar Ibragimov would explain more details. Ildar Ibragimov said that the lawyers of POMI told him that General Meeting of Department of Mathematics should approve a resolution saying that membership of Khrushchev in General meeting was illegal starting from 1992 when the General Meeting of RAS was formed. Moreover this resolution should be approved by Presidium. If this wouldn't be done then they couldn't complain the decision of a local court and moreover S.Khrushchev should be paid a moral demage of $6000. I took a word and tried to explain that we do not have time for discussion of this nonsense. Whatever decision would be made it would have no influence for the court because it couldn't correct the situation which existed at the moment of violation of the law when I sent my complain to the court. Moreover I said that no harm will be made to Department of Mathematics. I said that in case I win the complain of Faddeev's lawyers I will demand not Department of Mathematics but academic-secretary personally should pay a moral demage. However Buro members and especially Ildar Ibragimov insisted on continuation of this stupid discussion. The discussion followed occupied round 40 minutes. Many members of the meeting however agreed that Meeting of Department shouldn't discuss this topic because in one hour new Buro will be elected. Academician Sergei Nikol'skii said that first in 1992 Buro members claimed that creation of the Euler Institute was a very important task, next they claimed that its liquidation is very important and now they say that we should consider this juridical point. Why we discuss this question and do not discuss the real reasons for liquidation of the Euler Institute? Academician Vladimirov said that members of the meeting do not understand such subtle juridical matter and therefore a serious mistake can be made. So he suggested that the topic should be dropped. But Voevodin insisted. Voevodin mentioned that Khrushchev provided a help to the enemy of MIRAN (that is to Professor Larry Shepp). >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> REMARK This last claim deserves a speciale discussion at the end of this document. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Finally Voevodin insisted on voting and voted a new illegal decision which I already complained. This was done in spite of protests of such mathematicians like A.Vitushkin who demonstrated a very good juridical knowledge by saying that this decision just cannot enter the court because the decision of the first instance was already made. He claimed that he does not want to vote this matter. After a small break elections of a new academic-secretary and a new Buro started. Candidature of Faddeev was put in the list first. Next candidature of Ershov from Novosibirsk was included too by Lavrentiev. Lavrentiev with reference to my talk said that in contradistinction to Faddeev Ershov beeing a very good mathematician is a very good rector of Novosibirsk University and therefore is very experienced from the administrative point of view. Lavrentiev was interrupted by saying that this should be said later and shortly after that Ershov said that he did not want ballot in this company again. So Faddeev remained alone. Nontheless Sergei Novikov emotionally advocated for Faddeev and called him a hero. Sergei Novikov works abroad and just does not understand the difficulties existing in Russia now. Moreover he talked on the "achivements" of L.D.Faddeev with the reforms at the Euler Institute (actually its liquidation) without any study of the topic. He claimed that after reorganization Euler Institute became more open. This does not corresspond to the real state of things because in reality the number of visitors decreased more than ten times. Moreover a fence surrounding the building is at the place and the doors are locked while inside the Palace there are only dogs and security. After that it turned out that Faddeev was elected from one candidature. The result of election of Buro members was the following. All members remained in Buro with exception of Sergei Novikov who just refused to be elected. I consider this step of Sergei Novikov as a very principal step. >From my point this shows some progress in understanding that in difficult economic situation in Russia one should make a definite choice between administrative and organizational work in Russia and scientific work abroad. There were 45 members of General Meeting of Department of Mathematics. On the other hand Buro incorporates 17 members. Since academic-secretary should get at least 23 votes to be elected one can easily see that if Buro members support academic-secretary he needs only 6 extra votes. In Department of Mathematics membership in Buro has been always considered as a honorable matter. However nowadays this is in a direct contradiction with requirements of life. Department of Mathematics needs a working Buro. All branches of mathematics and important institutions should be present. This can be satisfied if Buro had say 10-12 people. Now in spite of the fact that Buro includes 17 mathematicians there is no Jewish mathematician in Buro. The only candidate Arnold did not get enough votes. This strange fact is in direct contradiction with what was said by academician Victor Maslov on the Meeting. As it is clear from the discussion scientific achivements of Faddeev for last years were put higher than terrible consequences of his administrative efforts. In contradistinction to Faddeev Arnol'd has never had such administrative achivements as Faddeev. On the other hand I hope many people agree that research made by Arnol'd is of great value for mathematics. So it is not clear why Department of Mathematics cannot live (following the claim made by Maslov) without Faddeev as academic-secretary but feels save without Arnol'd as a Buro member. It is especially interesting if such a big care (following Victor Maslov) was paid to the level of research of Buro members. Perhaps the explaination roots in words said by not experienced Chairman Voevodin. During the discussion on the court matter he said that we (Buro members) operate in a friendly atmosphier (=we are all friends) and take decisions almost unanimously. Therefore we never take a look of Ustav and Polozhenie because we just do not need them. I can only ask what is a name for a group of "friends" violating Laws and acting as officials on the basis of friend relations? Sergei Khrushchev PS Faddeev arived to the meeting from abroad and departed abroad the very last day of the meeting. Next day after departure of Faddeev our newspapers reported that academician Vladimir Nechaev, the creator of a nuclear center "Chelyabinsk-70", committed suicide because he as a Director could do nothing to provide money for salary of his scientists... >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> ADDENDUM ON THE ENEMY OF MIRAN >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> SUBJECT: WHAT ARE RULES AND IS THIS FAIR? I was given to understand that I am eligible to be considered for the position of the next Director of POMI. Now I learn that the search for the position has been closed and that my application was denied because my application did not satisfy a certain procedural requirement. No attempt was made to convey this procedural requirement to me and had it been, I would have tried to fulfill it, possibly with success. I demand that the search be reopened and that my candidacy be considered, or that I at least be given time to solicit the necessary support. People in Russia who know me well are aware of my deep interest in the success of mathematics in Russia and also in the future of democratic reform in Russian mathematics. This very example would seem to indicate how much Russia needs such reform. Lawrence Shepp ENCLOSED IS A COPY OF PROF. SHEPP's APPLICATION: To: Department of Mathematics, POMI FAX = 7-095-938-14-66 From: Lawrence Shepp, Columbia U, Dep'ts of Statistics and Operations Research, ATT Bell Labs, US National Academy of Science Subject: Directorship of the new organization in StP I learned from an announcement distributed by Sergei Khruschev that the Department of Mathematics has a new UCHREZHDENIE RAN "Sankt-Peterburgskoe Otdelenie Matematicheskogo Instituta im. V.A.Steklova". I understand from the announcement that the Directorship of this Institute is vacant and that the Director need not be Russian or a Russian citizen. As many know, I have been a frequent visitor to MIAN and POMI over the years and maintain an ongoing interest in the Institute and especially in the Russian mathematical community. I would like to be considered for the Directorship. I have recently retired from Bell Laboratories and have been actively seeking a new position. At the present time I have an offer from Rutgers U. and expect an offer from Columbia U., but I will give serious consideration to an offer for the POMI position as well. I understand from Khruschev's announcement that the new organization is not to be an Institute of RAS but an Uchrezhdenie. Please send me the Charter of the new organization so that I can study the rules of the election procedure and the job description of the new Director. Please confirm the receipt of this fax by either return fax to this number at Columbia U. or to the fax below at Bell Laboratories (where I continue to visit on a regular basis). Sincerely yours, Lawrence Shepp Lawrence A Shepp Columbia University; Statistics and Operations Research 212-854-3653 212-854-2941 shepp@stat.columbia.edu ATT Laboratories Room 2C-374 Murray Hill NJ 07974-0636 908-582-3585 FAX = 908-582-2379 las@research.att.com EXPLAINATION >> From: Larry Shepp >> A word of explanation as to my sincerity in seeking the position: I deem >> it unlikely that I would accept the terms of any offer that might be >> tendered by POMI RAN in any scenario even remotely consistent with >> reality. I advanced my candidacy in order to promote the principles of >> division of power in Russian mathematics which has long suffered from >> abuses of power concentration. I have had a long history of involvement in >> Russian mathematics and those who know me well realize my motivations are >> genuinely on the side of the success of Russian mathematics. I have no >> knowledge or opinion about the correctness of one or another side in the >> current struggles in St. Petersberg over POMI and the Euler Institute, >> but argue only that it is desirable to keep these institutions independent. >> These opinions were expressed more fully in a letter (joint with AM Kagan) >> see, Notices AMS April 6, 1996 (the text is enclosed below). >> I never received the courtesy of a reply to any of several successfully >> transmitted faxes announcing my candidacy, even that they were received. Letter to the editor, Notices AMS Information published in Science (23 June 1995, p.1695) and received recently from friends in Russia indicates that the Euler International Mathematical Institute (EIMI) in St. Petersburg which for many years existed as a separate unit similar to such institutes as the Banach Center in Warsaw, Oberwolfach in Germany, and DIMACS, IMA, and MSRI in the US may soon be subsumed into a department of the St. Petersburg Branch of the Steklov Mathematical Institute (POMI), Russian Academy of Sciences. To the best of our knowledge, the decision to fold EIMI into POMI resulted from a conflict between the director of EIMI, Ludwig Faddeev (who is also deputy director of the Steklov Mathematical Institute in charge of the St. Petersburg Branch) and his deputy in EIMI, Sergei Khrushchev. Faddeev claims that folding EIMI into POMI is in the best interests of St. Petersburg mathematicians while Khrushchev, who is losing his job at EIMI, says that placing it under the control of POMI will destroy EIMI as a center of international cooperation in mathematical research. While the final decision on the fate of EIMI rests in the hands of our Russian colleagues, we mathematicians in the West also have an interest in preserving EIMI and so have the right to at least make a suggestion and to add some thoughts to the discussion. We would like to see EIMI continue as a separate unit, with its own budget, run by an executive director, a capable scientist and administrator, who, however, serves at the pleasure of a Board of Trustees, which is independent of all other institutions, in the Western style. A number of Western organizations (the Soros Foundation, AMS, the European Mathematical Union, etc.) are providing, in different forms, financial support to the Russian mathematical community. It is thus reasonable to have, say, one trustee from the United States and one from Europe on the Board. Besides being instrumental in fund raising for EIMI, the Western trustees will bring to the Board needed expertise and independence. Abram M Kagan, U Maryland, College Park Lawrence A Shepp, Bell Laboratories, Murray Hill
On Sat, 9 Nov 1996, Joseph Edward Nemec wrote: > > And that would be the limit for an ambitious, uncultured bourgeois moron > from Newcastle. How sad... Good job I'm not from Newcastle then. > > Translation: I am not good enough at physics to get to the top. > Are you not Joe? How sad. to be honest with you though, life at the top isn't all that great. It just means that you are researching slightly different things to other people. Of course, I get to have a nice well known subject such as the Higgs, but that's about it. > > Well, aside from actually getting a Ph.D. in it... > I will hand in before I head off to the city. Probably. > > Soon to realize that you were duped... Shit, man, you're right. I ought to instead have gone to some anonymous institution. I'd havedone much better there, that's for sure. Then, instead of ending up a particle physicist, I could have become an expert in queuing theory. After all, it is THE fashionable subject of the day, isn't it? > > Soon to realize your country is second rate in that field... Oops, we were ten years ahead of the field. Never mind. > > Well, except for publishing distinguished work in the field... Been there, done that. > > Please send me a copy of that report. Please pay me 50 pounds, and I will send you a copy. You aren't getting one for free, that's for sure. You wouldn't understand it anyway. Peculiarly enough, it will be pretty technical, requiring knowledge beyond degree level of high energy physics. > > We don't think you are shallow. We just know that you will not make > several million dollars per year. No, all the people I know in the city are obvioulsy completely unrepresentative of what's out there. I am completely deluding myself that I will do the same as them. Well, at least I'm happy in my ignorance. > You are a failure at physics. Of course I am, of course. How foolish of me to think otherwise. > > Anthony, I would LOVE to test you on your knowledge of the stochastic > calculus... Now why doesn't that surprise me? > > Of course not: you are the sort of idiot who rails over the internet, and > hides behind his keyboard. That's right Joe. My boxing matches have all been carried out over the internet. In fact, now I think back, they weren't boxing matches at all, they were in fact just video games. > > Failure. > You oughtn't to sign yourself that way. Hell, just because you aren't going anywhere, it doesn't mean that your parents don't love you. And not all of us can get a place on the high energy physics courses, so don't feel too bad about yourself. Anthony Potts CERN, GenevaReturn to Top