Matrices with circular higher rank numerical range

Abstract: The rank-$k$ numerical range of a square matrix $A$ is the set of all complex numbers $c$ such that $PAP = cP$ for some rank-$k$ orthogonal projection $P$. (When $k=1$, this reduces to the classical numerical range.) We investigate conditions on when the rank-k numerical range is a circular disk. This talk is based on joint work with Ilya Spitkovsky and Hugo Woerdeman.

combinatoricscomplex variablesfunctional analysisgeneral mathematicsgroup theoryK-theory and homologynumber theoryoperator algebrasprobabilityquantum algebrarings and algebrasrepresentation theory

Audience: researchers in the discipline

GAG seminar

Series comments: Description: Non-specialized research seminar