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Is it true $tr(\mu\mu^{T}A) = \mu^{T}A\mu$, where $\mu$ is vector of opropriate order?

I verified it for $3\times3$ case.

Satya Prakash
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1 Answers1

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Yes. In general, regardless of the sizes of the matrices $X$ and $Y$, if $XY$ and $YX$ are legitimate matrix multiplications, then the two matrix products have the same nonzero eigenvalues and hence the same traces.

user1551
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