bio | website | grpaseman.wordpress.com |
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location | S.F. Bay Area | |
age | ||
visits | member for | 4 years, 11 months |
seen | Dec 18 at 19:07 | |
stats | profile views | 4,283 |
The sdfae.* websites are not up (technical difficulties); until they rise, I invite you to check out http://grpaseman.wordpress.com for the month of October and your dose of System Design.
Ask Me About System Design. I am willing to do email correspondence on the subject.
Social Networking Data
__Location: (Headed to) Back from Seoul for ICM2014. See MathOverflow @ ICM2014 : We Want You! for detail, including email address
__Interests: General Algebra, Computability, Enumeration, Prime Gaps
__Project: Bounds on Jacobsthal's Function
__Project: Combinatorics of P's Ring Toss
__Have: copy of Erik Westzynthius' (Only?) Paper
__Want: symbolic dynamics on infinite directed sets, esp. forests
__Contact: through Will Jagy, or guess the following Hangman dro_d__r_ard__ma_l.com
(Please do not merge keep me, or even merge me: merge keep 3402 instead)
Dec 17 |
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Graduate program applications that require questionnaires and other non-letter material
@KConrad the academia site is built for questions and answers with issues just like this. The only reason to specialize it to math and post it here is that much of the audience you want is here (and I pretend that you want to shirk or otherwise avoid other academic disciplines). That's why I recommend a link, not deletion. The topic is otherwise not mathematical and I would not like to see many of these kinds of questions on this forum. Of course, it is not for me to decide, but the community to accept/reject. Gerhard "Don't Make It A Habit" Paseman, 2014.12.17 |
Dec 17 |
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Graduate program applications that require questionnaires and other non-letter material
I applaud the intent behind the post; I decry its current location. Please submit to academia.stackexchange and add a link here to it. Of course, if the community decides otherwise... . Gerhard "For Keeping MathOverflow Primarily Mathematical" Paseman, 2014.12.16 |
Dec 16 |
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Does the Diophantine equation $(x^2+ay^2)(u^2+bv^2) = p^2+cq^2$ admit a complete solution?
I suspect part of the communication issue revolves around the phrase "complete solution". individ is producing things which, if they are solutions, leave no variable alone, and are complete in providing an answer for each variable. What is wanted (and which may be explained elsewhere, but I don't see it clearly yet) is a system of expressions which will capture ALL solutions of the original system, and in a nice way which allows easy and uniform generation of any solution: a "complete" and nice description of all solutions. Gerhard "Words: Can't Live Without 'Em" Paseman, 2014.12.16 |
Nov 29 |
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Sets of coprime numbers
Somewhat related are covering congruences, which are used to show certain expressions are never prime, such as 2^N + C. Erdos and Pomerance have some articles. You might also look up Guy's Unsolved Problems In Number Theory for similar problems. Gerhard "Going Off On A Tangent" Paseman, 2014.11.29 |
Nov 26 |
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Equitably distributed curve on a sphere
I imagine something like a hamiltonian circuit on a dodecahedron, extended to hamiltonians on a planar graph with metric borrowed from a stereographic projection. Perhaps what you want for large L are the inverse images ( under s. p. ) of approximations to space filling curves inside large disks. Gerhard "Such Thoughts Fill My Mind" Paseman, 2014.11.26 |
Nov 6 |
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Tower-of-squares sequence divides linear recurrent A001921 sequence?
OK. I was thinking 2x2 matrices with a' = (6 0) + Aa, and then calling this operation Va and trying V iterated to a high power. I haven't followed it up though. Gerhard "Maybe Smaller Will Be Better" Paseman, 2014.11.06 |
Nov 6 |
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Tower-of-squares sequence divides linear recurrent A001921 sequence?
Does any enlightenment occur when you write the a-recurrence in matrix form? Gerhard "Or Maybe Tilt Your Head" Paseman, 2014.11.06 |
Oct 3 |
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Prime divisors of the respectively minimal binomial coefficients
Wlod, I only see that Mersenne primes prevent the definability of G(2). Indeed, I believe one can prove B(2)=4 and I think it is not hard to show B(3) and G(3) exist and are larger than 8, but not by much. Gerhard "Or We're On Different Pages" Paseman, 2014.10.03 |
Oct 2 |
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Prime divisors of the respectively minimal binomial coefficients
You should also consider B(n) and G(n), which are the smallest values of b and g such that for all c >= b or h >= g, one has c choose n have at least n different prime divisors or h choose n have at least n different prime divisors greater than n. Stoermer's Theorem suggests to me that these values also exist. Gerhard "Wants Really Explicit Application Scope" Paseman, 2014.10.01 |
Oct 1 |
answered | what-if.xkcd.com: stabbing (simply connected) regions on the 2-sphere with few geodesics |
Oct 1 |
answered | Has philosophy ever clarified mathematics? |
Sep 29 |
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a colouring / matching problem
Also, I am interested in just tackling the problem instance; I doubt I will come up with anything not already considered twenty or more years ago by people working on PARTITION. But perhaps you can tell me the following: by focussing on (only those boxes having) number 11, then number 11 and 13, then 11,13,12, then 11,13,12,0, it looks like the number of valid colorings is bounded above by 1, 4 , g=4*(11!)/((2!)4!5!), g*(10!)/4!. As we add more numbers, does the number of valid colorings explode or level off? Gerhard "Picking The Problem Into Pieces" Paseman, 2014.09.29 |
Sep 29 |
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a colouring / matching problem
I'm thinking more about shortening: consider a coloring partly successful if it manages to color the boxes based on just the numbers 0-k for some positive integer k (or pick your favorite subset of 0-14). A short proof of infeasibility may arise from just attempting the colors 0-7. Ideally, for each coloring of the smallest boxes, toss out those colors and labels, and look for a feasible coloring of the remainder. Now shorten the vectors and see if an infeasibility proof arises from just looking at numbers 0 through 7, say. Gerhard "Merging Is Different From This" Paseman, 2014.09.29 |
Sep 29 |
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a colouring / matching problem
@Martin, how many mod 8 feasible colorings are there of the "smallest" boxes? In other words, how many ways are there of coloring the two boxes of two items and the four boxes of four items in such a way that when you are done, the remaining colors are each a multiple of 8? Also, do the "big" boxes fall into nice groups like half the boxes have numbers 1,2,3,4, 30% have numbers 6,7,8,10, and a much smaller remainder have some scattering? It may be that looking at the first six coordinates will suggest a coloring for the rest. Gerhard "Slicing Diagonally Might Also Help" Paseman, 2014.09.28 |
Sep 25 |
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a colouring / matching problem
If all the colors had a multiple of 8 labels, but every feasible coloring involved coloring the 2 distinct boxes of 2 items with different colors, you would get a mod 4 or mod 8 conflict. You can look for parity conflicts this way, or assume that they have to be resolved first and thus limit the available colorings of the "smallest" 13 boxes. At the moment, I see no other easy way to find a proof of infeasibility. Gerhard "Maybe Subtract Off Symmetric Boxes" Paseman, 2014.09.24 |
Sep 24 |
awarded | Autobiographer |
Sep 19 |
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Prime Hadamard Matrices
@Gerry, Peter Keevash's recent paper suggests that there may be only finitely many such n with 4n not the order of a real Hadamard matrix. Of course, complex Hadamard matrices exist of all orders. I have not studied his paper enough to convince myself that it applies to Hadamard designs, but it looks promising. Gerhard "Still Puzzling Over Random Constructions" Paseman, 2014.09.19 |
Sep 19 |
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Representing a number close to 1 with a sum of reciprocals of natural numbers
Since your question is short, adding about twice as much ink after the question to explain motivation is welcome. If it gets to ten times as much ink, consider abbreviating the motivation and providing a link to an expanded version. I don't see adding a separate answer for it yet as a good thing. Gerhard "Or Measure It In Pixels" Paseman, 2014.09.19 |
Sep 19 |
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a colouring / matching problem
The above assumes there is a feasible solution you wish to find. If you want to prove that there is no feasible solution, I suspect finding a small infeasible subset of boxes is your best hope. Gerhard "Doesn't Like Infeasible So Much" Paseman, 2014.09.19 |
Sep 19 |
answered | a colouring / matching problem |