Member Seminar 2021-22

During the 2021-22 academic year, the CMSA will be hosting a Member Seminar, organized by Itamar Shamir and Yingying Wu. This seminar will take place on Fridays at 9:30am – 10:30am (Boston time). The meetings will take place virtually on Zoom. All CMSA postdocs/members are required to attend the weekly CMSA Members’ Seminars, as well as the weekly CMSA Colloquium series.

The schedule below will be updated as talks are confirmed.

Fall 2021

DateSpeakerTitle/Abstract
9/3/2021CMSA Welcome Eventn/a
9/10/2021Michael SimkinTitle: Threshold phenomena in random graphs and hypergraphs

Abstract: In 1959 Paul Erdos and Alfred Renyi introduced a model of random graphs that is the cornerstone of modern probabilistic combinatorics. Now known as the “Erdos-Renyi” model of random graphs it has far-reaching applications in combinatorics, computer science, and other fields.

The model is defined as follows: Given a natural number $n$ and a parameter $p \in [0,1]$, let $G(n;p)$ be the distribution on graphs with $n$ vertices in which each of the $\binom{n}{2}$ possible edges is present with probability $p$, independent of all others. Despite their apparent simplicity, the study of Erdos-Renyi random graphs has revealed many deep and non-trivial phenomena.

A central feature is the appearance of threshold phenomena: For all monotone properties (e.g., connectivity and Hamiltonicity) there is a critical probability $p_c$ such that if $p >> p_c$ then $G(n;p)$ possesses the property with high probability (i.e., with probability tending to 1 as $n \to \infty$) whereas if $p << p_c$ then with high probability $G(n;p)$ does not possess the property. In this talk we will focus on basic properties such as connectivity and containing a perfect matching. We will see an intriguing connection between these global properties and the local property of having no isolated vertices. We will then generalize the Erdos-Renyi model to higher dimensions where many open problems remain.
9/17/2021Itamar ShamirTitle: Geometry, Entanglement and Quasi Local Data

Abstract: I will review some general ideas about gravity as motivation for an approach based on quasi local quantities.   
9/24/2021Puskar MondalTitle: Stability and convergence issues in mathematical cosmology


Abstract: The standard model of cosmology is built on the fact that while viewed on a sufficiently coarse-grained scale the portion of our universe that is accessible to observation appears to be spatially homogeneous and isotropic. Therefore this observed `homogeneity and isotropy’ of our universe is not known to be dynamically derived. In this talk, I will present an interesting dynamical mechanism within the framework of the Einstein flow (including physically reasonable matter sources) which suggests that many closed manifolds that do not support homogeneous and isotropic metrics at all will nevertheless evolve to be asymptotically compatible with the observed approximate homogeneity and isotropy of the physical universe. This asymptotic spacetime is naturally isometric to the standard FLRW models of cosmology. In order to conclude to what extent the asymptotic state is physically realized, one needs to study its stability properties. Therefore, I will briefly discuss the stability issue and its consequences (e.g., structure formation, etc). 
10/1/2021Jue Liu
10/8/2021Michael Douglas 
10/15/2021Juven Wang
10/22/2021Du Pei
10/29/2021Freid Tong
11/5/2021Chuck Doran
11/12/2021Gabriel Wong 
11/19/2021Kan Lin
12/3/2021Dan Kapec
12/10/2021Changji Xu
12/17/2021

Spring 2022

DateSpeakerTitle/Abstract
1/7/2022Bong Lian
1/14/2022Max Wiesner
1/21/2022Daniel Junghans

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