I have that $A$ is a matrix that has real eigenvalues, which are non-positive, but it is not a symmetric matrix. Also, $B$ is a positive semi-definite matrix that is diagonal. Does the following hold:
$$\text{Tr}\,(AB) \leq 0$$
I have that $A$ is a matrix that has real eigenvalues, which are non-positive, but it is not a symmetric matrix. Also, $B$ is a positive semi-definite matrix that is diagonal. Does the following hold:
$$\text{Tr}\,(AB) \leq 0$$
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No. For example take
$ A = \left( \begin{array}{ccc} -ab & -b \\ a & 1 \end{array} \right) $
$ B = \left( \begin{array}{ccc} 1 & 0 \\ 0 & 1+ab \end{array} \right) $
$A$ has eigenvalues $0$ and $1 - ab$, which are non-positive if $a, b$ are large. $B$ is positive definite if $a, b > 0 .$ We have: $ Tr(AB) = 1 > 0 .$