Some inequalities for the Hadamard product of matrices
The authors find the best possible bounds for certain functions of the eigenvalues of \((A\circ C)C^{-1}\), where \(A\) is a fixed positive definite (or semidefinite) \(n\times n\) matrix and \(C\) runs through all positive definite \(n\times n\) matrices. One result is that the infimum of the \(k\)th elementary symmetric function of the eigenvalues of \(A\) occurs when \(C=I\).
elementary symmetric function of the eigenvalues
scientific article; zbMATH DE number 951787