The structure of Schmidt subspaces of Hankel operators: a short proof
Volume 256 / 2021
Studia Mathematica 256 (2021), 61-71
MSC: 47B35, 30H10.
DOI: 10.4064/sm190717-7-2
Published online: 27 May 2020
Abstract
We give a short proof of the main result of a previous paper of ours: every Schmidt subspace of a Hankel operator is the image of a model space by an isometric multiplier. This class of subspaces is closely related to nearly $S^*$-invariant subspaces, and our proof uses Hitt’s theorem on the structure of such subspaces. We also give a formula for the action of a Hankel operator on its Schmidt subspace.
