Inequalities for spreads of matrix sums and products.
Jorma Kaarlo Merikoski, Ravinder Kumar · 2004
Let A and B be complex matrices of same dimension. Given their eigenvalues and singular values, we survey and further develop simple inequalities for eigenvalues and singular values of A + B, AB, andA◦B. Here ◦ denotes the Hadamard product. As corollaries, we find inequalities for additive and multiplicative spreads of these matrices. 1