Speaker: Charles Johnson (The College of William and Mary, VA, USA) 

Title: Orthogonal Zero Patterns

Date: 4th of June, 12h

Venue: Sala B4009 (sala de seminários do DMAT) , Departamento de Matemática

Online: : https://videoconf-colibri.zoom.us/j/93344876599?pwd=ejkrZ3FpYkh0NE1YV3NCdGFMOGw3QT09

Abstract: We discuss recent work on the zero/nonzero patterns that occur among n by n real orthogonal matrices. There is a universal necessary condition that is sufficient for n<5. But for n=5 there are 2 patterns that meet this condition and are not orthogonal. This is joint work with YuLin Zhang and Carla Ferreira.