291 reputation
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bio website mccme.ru/~akopyan
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visits member for 4 years, 9 months
seen Jun 15 '13 at 20:18

Apr
10
awarded  Nice Answer
Jul
30
comment A Weak Form of Borsuk's Conjecture
Dear Prof. Kalai, how many faces in your example?
Feb
1
awarded  Nice Answer
Jul
30
awarded  Commentator
Jul
30
comment (1-Lipschitz) + (length-preserving) = isometry
Here it is for high dimensional Euclidean case. cs.elte.hu/geometry/Workshop09/large_r5.pdf
Jul
29
revised (1-Lipschitz) + (length-preserving) = isometry
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Jul
29
answered (1-Lipschitz) + (length-preserving) = isometry
Jul
28
comment (1-Lipschitz) + (length-preserving) = isometry
Using that f is 1-Lipschitz and that [aa′] is a diameter, we get that β must be contained in the interior of α Why?
Apr
12
comment Is there a generalized Feuerbach point for an irregular non-Euclidean triangle?
I've found synthetic proof for it to the two dimensional non-Euclidean case. But article is in Russian. mccme.ru/free-books/matpros/mpd.pdf#page=155
Dec
26
answered What would you want to see at the Museum of Mathematics?
Nov
30
awarded  Yearling
Jul
11
comment Theorems in Euclidean geometry with attractive proofs using more advanced methods
This problem from IMO Shortlist. You can find solution for high school students in Prasolov book. But this problem is not so easy in hyperbolic geometry.
Jul
11
comment Theorems in Euclidean geometry with attractive proofs using more advanced methods
Every theorem from classical geometry has short and elegant proof for "high-school students". But one can find very difficult proof which use algebraic topology or category theory.
Jul
4
comment eBook readers for mathematics
It is not compfortable to read from netbook. iPad is good as bookreader.
Jul
4
answered eBook readers for mathematics
Jul
4
revised Parabolic envelope of fireworks
added 2 characters in body
Jul
4
revised Parabolic envelope of fireworks
added 8 characters in body
Jul
4
answered Parabolic envelope of fireworks
Apr
20
answered What are the most overloaded words in mathematics?
Apr
20
revised Minimum cover of partitions of a set
deleted 2 characters in body