Previous Conferences & Workshops

Nov
12
2015

Geometric Structures on 3-manifolds

Algebraic degrees and Galois conjugates of pseudo-Anosov stretch factors
4:00pm|S-101

We consider questions that arise naturally from the subject of the first talk. The have two main results: 1. In genus $g$, the algebraic degrees of pseudo-Anosov stretch factors include all even numbers between $2$ and $6g - 6$; 2. The Galois...

Nov
12
2015

Geometric Structures on 3-manifolds

Pseudo-Anosov constructions and Penner's conjecture
2:00pm|S-101

In this first talk, we give an introduction to Penner’s construction of pseudo-Anosov mapping classes. Penner conjectured that all pseudo-Anosov maps arise from this construction up to finite power. We give an elementary proof (joint with Hyunshik...

Nov
11
2015

Mathematical Conversations

Effective hyperbolic geometry
6:00pm|Dilworth Room

Powerful theorems of Thurston, Perelman, and Mostow tell us that almost every 3-dimensional manifold admits a hyperbolic metric, and that this metric is unique. Thus, in principle, there is a 1-to-1 correspondence between a combinatorial description...

Nov
11
2015

Minerva Distinguished Visitor Lectures at Princeton University

II: Dynamics on moduli spaces of hyperbolic surfaces
4:30pm|McDonnell A02, Princeton University

In the second lecture, I will discuss several natural geometric flows defined on bundles over the moduli spaces of curves. I will describe basic ergodic properties of these flows. I will discuss some open questions and some of the progress made in...

Nov
10
2015

Joint IAS/Princeton University Number Theory Seminar

On the Moy-Prasad filtration and supercuspidal representations
2:00pm

Reeder and Yu gave recently a new construction of certain supercuspidal representations of $p$-adic reductive groups (called epipelagic representations). Their construction relies on the existence of stable vectors in the first Moy-Prasad filtration...

Nov
10
2015

Computer Science/Discrete Mathematics Seminar II

Exponential separation of communication and external information
10:30am|S-101

We show an exponential gap between communication complexity and external information complexity, by analyzing a communication task suggested as a candidate by Braverman [Bra13]. Previously, only a separation of communication complexity and internal...

Nov
09
2015

Minerva Distinguished Visitor Lectures at Princeton University

I: Geometry and dynamics on hyperbolic surfaces
4:30pm|McDonnell A02, Princeton University

The first lecture will give some background on the geometry and dynamics on hyperbolic surfaces. I will give a brief overview of Teichmüller theory and properties of the mapping class groups and the space of geodesic currents. I will discuss some...

Nov
09
2015

Members’ Seminar

Hard Lefschetz theorem and Hodge-Riemann relations for combinatorial geometries
2:00pm|S-101

A conjecture of Read predicts that the coefficients of the chromatic polynomial of a graph form a log-concave sequence for any graph. A related conjecture of Welsh predicts that the number of linearly independent subsets of varying sizes form a log...

Nov
09
2015

Computer Science/Discrete Mathematics Seminar I

Cutting plane method: A faster algorithm for many (combinatorial) optimization problems
Yin Tat Lee
11:15am|S-101

Many polynomial-time solvable (combinatorial) optimization problems can be reduced to the feasibility problem and the intersection problem. In this talk, I will present the first nearly cubic time algorithm for both problems using a new cutting...