Mathematics Colloquium



Department of Mathematics
University of Nebraska at Omaha


WHEN:
Thursday April 20, 2:30-3:30PM

WHERE:
Durham Science Center, Room 256

WHAT:


Valentin Matache

UNO - Mathematics


will give a talk on

On Norms of and Distances between Composition Operators.


ABSTRACT:

Operators Cf on function spaces acting by composition to the right with a fixed selfmap f of some set are called composition operators of symbol f. We consider the Hilbert Hardy space of all functions analytic in the open unit disk having square summable Maclaurin coefficients. The norm of a composition operator acting on that space is known in few cases. Norm-distances between distinct composition operators are even less investigated. In this talk we will consider norm, respectively norm-distance, computations recently obtained by this author and others. Some open problems related to this topic will be presented.