Hub informal

Events can be found on calendar page, with code HI.

An informal seminar to connect researchers in Beijing and elsewhere.

Organizer: Will Donovan

Some talks are posted on researchseminars.org.

We sometimes use the following format, to promote conversation in online setting.

Talks

Emily Bain (Berkeley, Yau MSC)

Wed Apr 6 2022

Dimer models and the two-periodic weighted Aztec diamond

A dimer model is a probability distribution on the set of perfect matchings on a planar graph. Often, we want to study the correlations between dimers, but in general this is a hard problem. However, some progress has been made. It has been shown that there are three distinct phases (solid, liquid and gas) found in dimer models, characterized by the rate of decay of the two-point correlation functions. A dimer model often exhibits more than one of these phases, with distinct boundaries between phases, where some interesting behavior can be found.   In this talk, we will give an introduction to dimer models and describe the Kasteleyn solution for computing correlation functions. Then we will give some examples of models with a solid and liquid phase, before introducing the two-periodic weighted Aztec diamond, which is one of the simplest models to exhibit a gas phase. Finally, we will talk about what happens as we shrink the gas region to a point in a specific limit.

This is an introductory talk. No background knowledge is required.

Koji Shimizu (Berkeley)

Wed Apr 13 2022

Introduction to p-adic geometry

This talk is a general introduction to p-adic geometry and p-adic Hodge theory. We will discuss the Legendre family of elliptic curves and the Drinfeld half-plane to see some interesting features of the p-adic setup.

付鑫 FU Xin (BIMSA)

Tue Dec 5 2023

The quotient spaces of moment-angle complexes

Buchstaber-Panov introduced the notion of the moment-angle complex Z. It is defined by a union of certain product spaces of discs and circles with a natural action of a torus T. Topologically, a moment-angle complex allows us to understand a simplicial toric variety as its quotient Z/H, where H is a closed subgroup of T. The computation of the cohomology groups and cup products for such quotient spaces involves using techniques from combinatorics, algebras, and homotopy theory with applications in other fields. This talk summarises known results and problems in the research field of toric topology and reports on recent progress.