Seminario Teoría de Números UAM-ICMAT
THE ZERO SET OF THE INDEPENDENCE POLYNOMIAL OF A GRAPH 
 
SPEAKER: Martín Sombra (ICREA & UB) 
 
DATE: Tuesday, 29th January 2019 - 11:30 
 
VENUE: Aula 520, Módulo 17, Departamento de Matemáticas, UAM 
 
ORGANISER: UAM - ICMAT 
 
ABSTRACT: In statistical mechanics, the independence polynomial of a 
graph G arises as the partition function of the hard-core lattice gas model 
on G. The distribution of the zeros of these polynomials when G → ∞ is 
relevant for the study of this model and, in particular, for the 
determination of its phase transitions. 
In this talk, I will review the known results on the location of these zeros, 
with emphasis on the case of rooted regular trees of fixed degree and 
varying depth k ≥ 0. Our main result states that for these graphs, the zero 
sets of their independence polynomials converge as k → ∞ to the 
bifurcation measure of a certain family of dynamical systems on the 
Riemann sphere. 
This is ongoing work with Juan Rivera-Letelier (Rochester).