Re: [math-fun] A linear algebra theorem?

http://mathoverflow.net/questions/50120/eigenvalues-of-matrix-product implies that the product of two Hermitian matrices is diagonalisable with real eigenvalues of the same signs as the second factor, and gives Prop 6.1 of Denis Serre's _Matrices_ as a reference. -Thomas C On Mon, Mar 28, 2011 at 3:42 PM, Eugene Salamin <gene_salamin@yahoo.com> wrote:

Is this a theorem?

Let A and B be real symmetric matrices all of whose eigenvalues are positive. Then all eigenvalues of AB are positive.

 --  Gene

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