On the kernel of a singular integral operator with shift

Some estimates for the dimension of the kernel of the singular integral operator I - cUP(+) : L-p(n)(T) -> L-p(n)(T), p is an element of (1, infinity), with a non-Carleman shift are obtained, where P+ is the Cauchy projector, U is an isometric shift operator and c(t) is a continuous matrix functi...

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Bibliographic Details
Main Author: Marreiros, Rui (author)
Format: article
Language:eng
Published: 2018
Online Access:http://hdl.handle.net/10400.1/11201
Country:Portugal
Oai:oai:sapientia.ualg.pt:10400.1/11201
Description
Summary:Some estimates for the dimension of the kernel of the singular integral operator I - cUP(+) : L-p(n)(T) -> L-p(n)(T), p is an element of (1, infinity), with a non-Carleman shift are obtained, where P+ is the Cauchy projector, U is an isometric shift operator and c(t) is a continuous matrix function on the unit circle T. It is supposed that the shift has a finite set of fixed points and all the eigenvalues of the matrix c(t) at the fixed points, simultaneously belong either to the interior of the unit circle T or to its exterior. The case of an operator with a general shift is also considered. Some relations between those estimates and the resolvent set of the operator cU are pointed out.