Past Events

E.g., Apr 15, 2024

Amir Moradifam


Rigidity of Hawking Mass for Stable Constant Mean Curvature Spheres

April 4, 2024

ESB 4133

In this talk, I will discuss recent work in which we establish the rigidity of the Hawking mass for stable constant mean curvature spheres, addressing a problem posed by Robert Bartnik in 2002. More precisely, we demonstrate that any complete Riemannian three-manifold with non-negative scalar... Read more

  • Differential geometry
  • Mathematical Physics
  • Partial Differential Equations

Paul Péringuey

UBC
Refinements of Artin's primitive root conjecture

April 4, 2024

ESB 4133

Let $ord_p(a)$ be the order of $a$ in $(\mathbb{Z}/p\mathbb{Z})^*$. In 1927 Artin conjectured that the set of primes p for which a given integer a (that is neither a square number nor −1) is a primitive root (i.e. $ord_p(a)=p-1$) has a positive asymptotic density among all primes. In 1967 Hooley... Read more

  • Number Theory

Duncan Dauvergne

University of Toronto
The directed landscape from Brownian motion

April 3, 2024

The KPZ (Kardar-Parisi-Zhang) universality class is a loose term for a collection of random interface growth models and random planar metrics that exhibit the same behaviour under rescaling. Examples of models in this class include TASEP, last passage percolation, and the KPZ equation. The... Read more

  • Probability

Elias Ventre

UBC Math
A theory of trajectory inference for time-courses of gene expression data

April 3, 2024

ESB 4133

A core challenge for modern biology is how to infer the trajectories of individual cells from population-level time courses of high-dimensional gene expression data. Birth and death of cells present a particular difficulty: existing trajectory inference methods cannot distinguish variability in... Read more

  • Mathematical Biology

Rachel Greenfeld

IAS
Integer distance sets

April 2, 2024

ESB 4133 (PIMS library)

A set S in the Euclidean plane is an integer distance set if the distance between any pair of its points is an integer. Interestingly, all the so-far-known integer distance sets have all but up to four of their points on a single line or circle. And it had long been suspected, going back to... Read more

  • Discrete mathematics

Yanwen Luo

SFU
Deforming geometric triangulations of surfaces with Tutte's embeddings and their generalizations

March 27, 2024

ESB 4133 (PIMS lounge)

The diffeomorphism groups of smooth surfaces are classical objects in low dimensional topology. In this talk, we will introduce the deformation spaces of geodesic triangulations as natural discrete analogues of these groups. We will talk about a general framework to identify their homotopy types... Read more

  • Topology

Foster Tom

MIT
A signed e-expansion of the chromatic quasisymmetric function

March 26, 2024

HTTPS://UBC.ZOOM.US/J/67626378782?PWD=SHAZL1KWTMCYYM1PDKDZNVNLNUZ6DZ09

We prove a new signed elementary symmetric function expansion of the chromatic quasisymmetric function of any natural unit interval graph. We then use sign-reversing involutions to prove new combinatorial formulas for melting lollipops and for K-chains, which are formed by joining cliques at... Read more

  • Discrete mathematics

Kyle Yip

University of British Columbia
UBC HAFG Seminar: Erdős similarity problem in the large

March 25, 2024

ESB 4133 (PIMS Library)

The celebrated Erdős similarity problem asks if it is always possible to construct a set of positive Lebesgue measure that does not contain any (nontrivial) affine copy of a given infinite set. The problem remains widely open. In this talk, I will discuss an analogue of Erdős similarity problem... Read more

  • Harmonic Analysis and Fractal Geometry

Shubhodip Mondal

UBC
Dieudonne theory and cohomology of classifying stack

March 25, 2024

MATH 126

In this talk, I will first describe how the classical Dieudonne module of finite flat group schemes and p-divisible groups can be recovered from crystalline cohomology of classifying stacks. Then I will explain how to classify finite flat group schemes over a fairly general base by using... Read more

  • Algebra and Algebraic geometry

Peter Kosenko

UBC
Classifying stationary measures on $S^1$ with respect to $PSU(1,1)$ through the complex-analytic point of view

March 25, 2024

ESB 4127

Given an arbitrary probability measure $\mu$ on $PSU(1,1)$, understanding the structure of $\mu$-stationary measures is a notoriously difficult problem, in particular, due to the number of different settings one can work in. The answer is known to depend on the moment conditions of $\mu$,... Read more