For matrix $A_{ntimes n},X_{ntimes p}$, $rank(X)=p$. Prove that if $M(X)subset M(A)$, $X^TAX>0$.
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Since $M(X)subset M(A)$ , I know that there exist a matrix B, s.t. $X=AB$ . Since $rank(X)=p$ ，I know that X is full rank, which means $Xy=0$ only has zero solution. But I don't know how to complete the proof.
linear-algebra
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asked Dec 22 '18 at 11:47
chole chole
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Hi what is $M$?
