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10 votes
3 answers
1k views

Number of permutations with longest increasing subsequences of length at most $n$

Is there a known expression for, or a nontrivial upper bound on, the number of permutations in $S_k$ with longest increasing subsequence of length at most $n$? Let $l(\sigma)$ denote the length of the ...
4xion's user avatar
  • 201
23 votes
2 answers
859 views

Moments of Plücker coordinates on complex Grassmannian

Consider the Grassmannian $Gr(k,N)\simeq U(N)/(U(k)\times U(N-k))$ which parametrizes $k$-dimensional subspaces of $\mathbb{C}^N$. Let us put on it the $U(N)$-invariant probability measure. Let $\...
Abdelmalek Abdesselam's user avatar
18 votes
5 answers
3k views

Moments of the trace of orthogonal matrices

Let $O_n$ be the (real) orthogonal group of $n$ by $n$ matrices. I am interested in the following sequence which showed up in a calculation I was doing $$a_k = \int_{O_n} (\text{Tr } X)^k dX$$ where ...
J. E. Pascoe's user avatar
  • 1,429
18 votes
0 answers
469 views

Quasi-classical limit of representation theory

I am looking for a good reference on a general phenomenon of quasi-classical limit in representation theory, which relates "large" representations to measures on (co-adjoint orbits of) the associated ...
Leonid Petrov's user avatar