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bio website math.kth.se/~eaas
location Sweden
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visits member for 2 years, 5 months
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Sep
9
comment Strange factorial identity
From OEIS it seems the number of elements in G_{n,k} should be the number of n-permutations with exactly k consecutive cycles (oeis.org/A184184). I cannot see whether your bijection proves this stronger claim.
Sep
3
comment Game involving points on $[0,1]$
@ChristianBlatter: Nice graph! It'd be interesting to see it for larger n. If one wants one of the final points to be 0, then one cannot do better than (1+a)/2^(n-2). Otherwise, the final points are 1/2^k and a/2^l for some (k,l) such that k+l <= n-2. I don't think that distance can be made smaller than 1/2^(n-2) in general (in particular, not for a = 3/4 and n = 7).
Sep
3
comment Game involving points on $[0,1]$
It seems to me that (0, ..., 0, a, 1) is harder for general a than a = 0, so 2^(-n+2) should not be sharp.
Mar
7
revised How to ensure Topological Correctness
equal linking numbers != equivalent links
Mar
7
suggested suggested edit on How to ensure Topological Correctness
Mar
7
comment How to ensure Topological Correctness
@KevinCarlson ah yes - I forgot about this. However it seems solving that problem would be asking for (at least) ways of distinguishing the unknot, which I think is difficult.
Dec
6
awarded  Nice Question
Nov
6
revised Vague question about polynomials and symmetry
f(x,y)->f(y,x)
Nov
5
asked Vague question about polynomials and symmetry
Jul
17
asked Fundamental domain of $\operatorname{GL}(n,\mathbb R)$ acted on by $\operatorname{GL}(n, \mathbb Z)$
Jul
7
awarded  Editor
Jul
7
revised Symmetric functions of the eigenvalues of A+B, A, B, ABA, BAB, et.c.
/ /k!
Jul
7
comment What about other symmetric functions of the eigenvalues?
Fair enough. math.stackexchange.com/questions/167978
Jul
7
asked Symmetric functions of the eigenvalues of A+B, A, B, ABA, BAB, et.c.
Jul
7
comment What about other symmetric functions of the eigenvalues?
@QiaochuYuan : I would be interested in unclosing this question, since there are generalizations which are not of the kind you mention in your old answer. For example, $i_2(A+B) = i_2(A)+i_2(B) +i_1(A)i_1(B) - i_1(AB)$. This can be found just by comparing coefficients of det(I+tX) for various X, but I have not found a 'unified' answer (expressing the analogous thing for i_k(A+B) in a conceptual way).
Jun
3
awarded  Supporter
Jun
3
comment What about other symmetric functions of the eigenvalues?
Thanks for your answer (the old one in particular)!
Jun
3
awarded  Student
Jun
3
asked What about other symmetric functions of the eigenvalues?