Means of unitaries, conjugations, and the Friedrichs operator
Authors:
Stephan Ramon Garcia
Affiliation:
Department of Mathematics, Pomona College, Claremont, CA 91711, USA
Abstract:
If C is a conjugation (an isometric, conjugate-linear involution) on a separable complex Hilbert space H, then T∈B(H) is called C-symmetric if T=CT∗C. In this note we prove that each C-symmetric contraction T is the mean of two C-symmetric unitary operators. We discuss several corollaries and an application to the Friedrichs operator of a planar domain.