Recent content by wrxue

My thought is $$CS(ABA^T)\subseteq CS(AB)\subseteq CS(A)$$ so the dimensions of ##CS(\cdot)## $$dim(CS(ABA^T))\leq dim(CS(AB))\leq dim(CS(A))=Rank(A)\leq (min(N,M))$$ thus $$dim(CS(ABA^T))\leq N$$ And $$rank(ABA^T)=dim(CS(ABA^T))\leq N<M$$ ##ABA^T## must be singular Just thought of it

But in this example, N(=2)>M(=1).

No, B can be any matrix. No more conditions. Q_Q

A' is transpose of A

I don't know how to do. Thanks in advance.