Convex function of diagonals and eigenvalues

1 · John Cook · June 18, 2020, 3:03 p.m.
Sam Walters posted an elegant theorem on his Twitter account this morning. The theorem follows the pattern of an equality for linear functions generalizing to an inequality for convex functions. We’ll give a little background, state the theorem, and show an example application. Let A be a real symmetric n×n matrix, or more generally a […]...