

Title: Has anyone seen this before? Post by BenVitale on May 7^{th}, 2009, 5:30pm I came across quite accidentally this forum where it discusses http://eqworld.ipmnet.ru/forum/viewtopic.php?f=3&t=128 I'm not familiar with "structural geometry" Then, on the same site, I found at http://eqworld.ipmnet.ru/forum/viewtopic.php?f=3&t=143 y = x^{2} + 16 y' at x=3 the author finds y'= 10 ... it's quite extraordinary! Okay, this result is bogus. But what about the socalled "structural geometry" at the first link ? 

Title: Re: Has anyone seen this before? Post by towr on May 8^{th}, 2009, 12:12am There's probably a reason why all replies in that thread are spam. It's not clear what he's trying to do, nor are his equations even correct in many cases. 

Title: Re: Has anyone seen this before? Post by Noke Lieu on May 8^{th}, 2009, 1:03am It's awesome it's like a ghost town or something. ) registered users, 1 guest, when I looked. 

Title: Re: Has anyone seen this before? Post by BenVitale on Jun 29^{th}, 2009, 12:15pm We start with 2 The second digit is twice the first, the third is twice the second, etc., with "carries" added in as we go along ... and then we stop when we find a number starting with 10. ................................2 ..............................42 ............................842 ........................16842 ......................136842 ......................736842 ..................14736842 ..................94736842 ..............1894736842 ............17894736842 ..........157894736842 ........1157894736842 ........3157894736842 ......63157894736842 ...1263157894736842 ...5263157894736842 105263157894736842 Moving the last 2 to the front gives 210526315789473684, manifestly twice 105263157894736842. This blog (http://tierneylab.blogs.nytimes.com/2009/04/10/puzzleanswersfromfreemandysonandafourthgrader/) also contains Dr. Mutalik's explanation of the phenomenon in terms of arithmetic mod 19. 

Title: Re: Has anyone seen this before? Post by towr on Jun 29^{th}, 2009, 12:34pm http://en.wikipedia.org/wiki/Parasitic_number 

Title: Re: Has anyone seen this before? Post by BenVitale on Jun 29^{th}, 2009, 1:23pm on 06/29/09 at 12:34:50, towr wrote:
Thanks for the link. These numbers are intriguing. 

Title: Re: Has anyone seen this before? Post by BenVitale on Jul 14^{th}, 2009, 12:08pm Has anyone done this experiment: http://www.youtube.com/watch?v=UB1vd8614gg 

Title: Re: Has anyone seen this before? Post by TenaliRaman on Jul 14^{th}, 2009, 1:25pm http://en.wikipedia.org/wiki/Reed%E2%80%93Solomon_error_correction#Data_storage  AI 

Title: Re: Has anyone seen this before? Post by BenVitale on Sep 18^{th}, 2009, 2:57pm Binary Clock (http://joerg.pretz.de/) It has a detail PDF document (http://joerg.pretz.de/uhr_art_eng.pdf) 

Title: Re: Has anyone seen this before? Post by BenVitale on Sep 28^{th}, 2009, 2:09pm Have you seen this book : A = B (http://www.math.upenn.edu/~wilf/AeqB.pdf)? 

Title: Re: Has anyone seen this before? Post by BenVitale on Oct 13^{th}, 2009, 1:55pm The Book of Odds (http://www.bookofodds.com/) is an online statistical encyclopedia. The Book of Odds is a searchable online database of “odds statements,” the probabilities of everyday life. 

Title: Re: Has anyone seen this before? Post by BenVitale on May 12^{th}, 2010, 7:14pm I've just read the following: The sum of digits of prime numbers is evenly distributed (http://www.physorg.com/news192907929.html) 

Title: Re: Has anyone seen this before? Post by BenVitale on Sep 8^{th}, 2010, 10:44pm Furstenberg's Proof of the Infinitude of Primes Quote:
http://primes.utm.edu/notes/proofs/infinite/topproof.html What makes this proof so strange? 

Title: Re: Has anyone seen this before? Post by rmsgrey on Sep 9^{th}, 2010, 7:25am on 09/08/10 at 22:44:40, BenVitale wrote:
If you look at the other proofs listed on that site, they are all couched in the language of arithmetic. They talk about taking a list of distinct primes (or a list of numbers that represent distinct primes), performing arithmetic operations on them, and producing a number that represents a new prime. The topological proof is, unsurprisingly, couched in the language of topology, so, while it's actually saying pretty much the same thing as the other proofs  that no finite set of primes can cover the integers with their multiples  there will always be some numbers that aren't divisible by any of the primes in the set, it's saying it in an unusual way. Also, it's a nonconstructive existence proof  it doesn't tell you anything about how to find these nonmultiples, just that they must exist  the other proofs all tell you where to look for your new prime. 

Title: Re: Has anyone seen this before? Post by BenVitale on Nov 30^{th}, 2011, 2:42pm A regular expression to check for prime numbers http://www.noulakaz.net/weblog/2007/03/18/aregularexpressiontocheckforprimenumbers/ 

Title: Re: Has anyone seen this before? Post by towr on Nov 30^{th}, 2011, 10:11pm It actually checks for nonprimes :P And it's a bit irregular for a regular expression, since you can't translate it to a finite state machine. 

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