Canonical Wiener-Hopf factorization on the unit circle: matching subspaces versus Riccati equations

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: ter Horst, Sanne, Kurula, Mikael, Ran, Andre
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866908565166358528
author ter Horst, Sanne
Kurula, Mikael
Ran, Andre
author_facet ter Horst, Sanne
Kurula, Mikael
Ran, Andre
contents Wiener-Hopf factorization is an important tool in the study of block Toeplitz and block Wiener-Hopf operators, and many applications involving these operators. In this paper we compare two approaches to Wiener-Hopf factorization, namely, the more classical approach based on matching invariant subspaces and a more recent approach based on solutions to a non-symmetric Riccati equation. The latter approach is extended to the case of Hilbert space operator-valued functions that are analytic on a neighborhood of the unit disc $\BT$, but need not be rational. In both approaches, existence of canonical right Wiener-Hopf factorization is characterized by existence of a stabilizing solution to a Riccati equation, however, the Riccati equations are not the same. We analyse the solution sets of the Riccati equations and show that they indeed are not the same, but they do have the same stabilizing solution.
format Preprint
id arxiv_https___arxiv_org_abs_2509_24337
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Canonical Wiener-Hopf factorization on the unit circle: matching subspaces versus Riccati equations
ter Horst, Sanne
Kurula, Mikael
Ran, Andre
Functional Analysis
47A63, 47A48, 47A56, 93B28, 93C05
Wiener-Hopf factorization is an important tool in the study of block Toeplitz and block Wiener-Hopf operators, and many applications involving these operators. In this paper we compare two approaches to Wiener-Hopf factorization, namely, the more classical approach based on matching invariant subspaces and a more recent approach based on solutions to a non-symmetric Riccati equation. The latter approach is extended to the case of Hilbert space operator-valued functions that are analytic on a neighborhood of the unit disc $\BT$, but need not be rational. In both approaches, existence of canonical right Wiener-Hopf factorization is characterized by existence of a stabilizing solution to a Riccati equation, however, the Riccati equations are not the same. We analyse the solution sets of the Riccati equations and show that they indeed are not the same, but they do have the same stabilizing solution.
title Canonical Wiener-Hopf factorization on the unit circle: matching subspaces versus Riccati equations
topic Functional Analysis
47A63, 47A48, 47A56, 93B28, 93C05
url https://arxiv.org/abs/2509.24337