2 problems

Let $\boldsymbol{A}$ be a matrix, let $\boldsymbol{A}_k$ be its best rank-$k$ approximation, and let $\boldsymbol{U}_k$ contain the top-$k$ left singular vectors of…

Let $\boldsymbol{A}$ be a positive semidefinite matrix with eigenvalues $\sigma_1\geq\cdots\geq\sigma_n\geq0$, let $\boldsymbol{U}_k$ contain its top-$k$ eigenvectors, and let $p$…