YouTube recording: https://www.youtube.com/watch?v=5ID6ZX20_is

Time: Thursday, May 11, 3pm ET
Zoom: https://uwaterloo.zoom.us/j/8674047206?pwd=RjVGV1duUHJPbEpZTWdRR3BLSld4Zz09
ID: 867 404 7206
Passcode: knauer1

Speaker: Kolja Knauer, Universitat de Barcelona
Title: Complexes of oriented matroids and their tope graphs

Abstract: Complexes of oriented matroids (COMs) arise from the combinatorics of a real hyperplane arrangement intersected with an open convex set. They generalize (affine) oriented matroids and capture various other classes such as convex geometries, antimatroids, CAT(0)-cube and Coxeter complexes, lopsided and ample set systems. I will give a gentle introduction and then focus on the tope graph of a COM – an object that determines the COM up to isomorphism. I will present a purely graph theoretic polynomial time verifiable characterization that specializes to oriented matroids.