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# Events for 01/29/2018 from all calendars

## Probability Seminar

## Working Seminar in Groups, Dynamics, and Operator Algebras

## Hiring Candidate - Dr. Chun-Hung Liu

## Student/Postdoc Working Geometry Seminar

**Time:** 2:00PM - 3:00PM

**Location:** BLOC 628

**Speaker:** paul jung, Korea Advanced Institute of Science and Technology

**Title:** *Infinite-volume Gibbs measures for the 1D-Coulomb jellium*

**Abstract:** The jellium is a model, introduced by Wigner, for a gas of electrons moving in a uniform neutralizing background of positive charge. In two dimensions, the model is related to the Gaussian free field while in one dimension the model is used to study dimerization and crystallization. For the quantum 1D jellium, Brascamp and Lieb (1975) proved crystallization (non-ergodicity of the Gibbs measures) at low densities of electrons. Using tools from probability theory including the Feyman-Kac formula and Markov chains, we demonstrate crystallization for the quantum one-dimensional jellium at all densities.

**Time:** 3:00PM - 4:00PM

**Location:** BLOC 628

**Speaker:** Xin Ma, Texas A&M University

**Title:** *Exact groups*

**Time:** 4:00PM - 5:00PM

**Location:** BLOC 220

**Speaker:** Dr. Chun-Hung Liu, Princeton University

**Description:**

Title: Graph minors and topological minors

Abstract:

Minors and topological minors are two closely related graph containment relations that have attracted extensive attentions. Though giant breakthroughs on graph minors have been made over decades, several questions about these two relations remain open, especially for topological minors. This talk addresses part of our recent work in this direction, including a proof of Robertson's conjecture on well-quasi-ordering graphs by the topological minor relation, a complete characterization of the graphs having the Erdos-Posa property with respect to topological minors which answers a question of Robertson and Seymour, and a proof of Thomas' conjecture on half-integral packing. More open questions, such as Hadwiger's conjecture on graph coloring and its variations and relaxations, will be discussed in this talk.

**Time:** 5:00PM - 6:00PM

**Location:** BLOC 628

**Speaker:** E. Ventura, TAMU

**Title:** *How to write down some interesting polynomials of degrees 19 and 20.*

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