GENERAL
SEMINAR

“The ubiquity of operator
ranges”

by

AURELIAN
GHEONDEA

Bilkent University

Abstract: An operator range
is a notion which deserves a definition only in infinite dimensional
topological spaces, so this topic seems to be, from the very beginning, very
narrow. Actually, operator ranges have been considered by the founders of
operator theory J. von Neumann, G. Mackey, J. Dixmier,
and many others, in order to understand the domains of unbounded closed
operators in Hilbert spaces. However, this notion took a
unexpected impetus from some electrical engineers who introduced two strange
operations for matrices called "parallel addition" and "shorted operator".
These two notions proved to provide a novel perspective in operator theory and
operator algebras that went further than probably they could foresee. In our
talk, we will make a review of the ideas related to operator ranges and point
out their appearance in connection with problems in analysis and mathematical
physics.

Date : November 10, 2010 (Wednesday)

Time : 15.40

Place: Bilkent University ,Mathematics Seminar Room SA141

Tea will be served before the seminar.