Article ID Journal Published Year Pages File Type
4602044 Linear Algebra and its Applications 2009 9 Pages PDF
Abstract

We provide a new and more efficient proof of our earlier result that every 2×2 Toeplitz matrix M has a representing measure μ that is optimal in the sense that ‖μ‖=‖M‖S, the norm of M as a Schur multiplier. This result is seen to follow from some elementary observations about extreme points in the unit ball of trigonometric trinomials. We also discuss the complete characterization of such extreme points.

Related Topics
Physical Sciences and Engineering Mathematics Algebra and Number Theory