Abstracts for the Seminar
 Discrete Geometry and Combinatorics
 Fall 2014

Speaker:  Thomas McConville, UMN
Title: Biclosed sets in real hyperplane arrangements
Time: 2:30 PM, Monday, November 24, 2014
Place:  Malott 206

Abstract: The set of chambers of a real hyperplane arrangement may be ordered by separation from some fixed chamber. When this poset is a lattice, Bjorner, Edelman, and Ziegler proved that the chambers are in natural bijection with the biconvex sets of the arrangement. For finite reflection arrangements, this result may be strengthened to a bijection between chambers and biclosed sets. In this talk, we extend this characterization of chambers to a wider class of arrangements, and we apply this result to study graphs of reduced galleries.