Hereditary Chip-Firing Models and Spanning Trees

Combinatorics Seminar
Friday, October 26, 2012 - 3:05pm
1 hour (actually 50 minutes)
Skiles 005
School of Math, Georgia Tech
A hereditary chip-firing model is a chip-firing game whose dynamics are induced by an abstract simplicial complex \Delta on the vertices of a graph, where \Delta may be interpreted as encoding graph gluing data. These models generalize two classical chip-firing games: The Abelian sandpile model, where \Delta is disjoint collection of points, and the cluster firing model, where \Delta is a single simplex. Two fundamental properties of these classical models extend to arbitrary hereditary chip-firing models: stabilization is independent of firings chosen (the Abelian property) and each chip-firing equivalence class contains a unique recurrent configuration. We will present an explicit bijection between the recurrent configurations of a hereditary chip-firing model on a graph G and the spanning trees of G and, if time permits, we will discuss chip-firing via gluing in the context of binomial ideals and metric graphs.