Speaker: Heydar Radjavi (University of Waterloo)

Title: Operators With Compatible Corners


 If the matrix of a linear operator A relative to an orthonormal decomposition of the underlying space is written in the 2 x 2 block form X  Y Z  T then we call Y and Z the off-diagonal corners of A with respect to this decomposition.  A leading example of what we call compatible corners is the special case of Hermitian operators where we have Y=Z*, so that Y and Z have the same norm and the same rank, among other things. We investigate the situations, in finite and infinite dimensions, in which the off-diagonal corners of an operator always have the same rank or the same norm.

 At least the first half of the talk should be accessable to graduate and even advanced undergraduate students.





#319 Colloquium Room, Chase Building