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15 votes
1 answer
518 views

Pairs of matrices for which traces of powers are independent of the order

Let $A,B$ be $n\times n$ matrices over ${\mathbb C}$ such that, for all $m,k$ and all partitions $(i_1,\ldots ,i_r)$ of $m$ and $(j_1,\ldots ,j_r)$ of $k$ (perhaps with some zero parts), $${\rm tr}\, (...
Paul Levy's user avatar
  • 1,336
6 votes
0 answers
192 views

Bar notation in Bourbaki’s *Lie groups*, Chap. IX

I am looking at Chapter IX (Compact Real Lie Groups), §4, Exercise 8 (translation). Given a complex subspace $\mathfrak p$ in the complexification $\mathfrak g_{\mathbf C}$ of some $\mathfrak g$, they ...
Francois Ziegler's user avatar
2 votes
1 answer
120 views

Can Hom-Lie algebras be seen as an $\Omega$-algebras?

An $\Omega$-algebra over a field $K$ is a $K$-algebra $A$ with a set of multilinear operators $\Omega$, where $\Omega=\bigcup_{m=1}^{\infty} \Omega_{m}$ and each $\Omega_{m}$ is a set of $m$-array ...
user118746's user avatar
4 votes
2 answers
360 views

Double centralizer in special linear algebra

It is well known that for a matrix $A$ in $\mathfrak{sl}_n(\mathbb{C})$, we have the following equivalence: $$\dim Z(A) \text{ is minimal} \leftrightarrow A \text{ is cyclic}$$ where $Z(A)$ is the ...
AThomas's user avatar
  • 617
2 votes
1 answer
207 views

Question on the proof of any finite dimensional module of a semisimple Lie algebra is semisimple

I'm going through a proof of the theorem, any finite dimensional module of a semisimple Lie algebra is semisimple, from page 10 of these notes (pdf). I am having a difficult time understanding few ...
Johnny T.'s user avatar
  • 3,625
5 votes
0 answers
428 views

Weyl's construction for symplectic groups--an exercise in Fulton and Harris's book

This is an exercise in section 17.3 in Fulton and Harris's book:Representation theory-a first course. Let $V=\mathbb{C}^{2n}$ and $Sp(2n)$ be the symplectic group w.r.t the nondegenerate bilinear ...
yang's user avatar
  • 181