# Events for 11/23/2020 from all calendars

## Colloquium - Stephan Wojtowytsch

**Time: ** 1:00PM - 2:00PM

**Location: ** Zoom

**Speaker: **Stephan Wojtowytsch, Princeton University

**Description: ****Title:** Beating the curse of dimensionality in machine learning?
**Abstract:** In the last two decades, machine learning has facilitated breakthroughs in fields as diverse as image classification, natural language processing and artificial intelligence for strategy games. A common task in these applications is approximating functions on very high-dimensional spaces. Neural networks form a non-linear function class, which appears to be uniquely suited to this task in which linear function classes fail in many examples. In this presentation, we discuss some challenges of high-dimensional analysis and the reasons behind the success of artificial neural networks as well as their limitations.

## Geometry Seminar

**Time: ** 3:00PM - 3:50PM

**Location: ** zoom

**Speaker: **Tom Gannon, University of Texas

**Title: ***Recovering Lie(G)-Modules from the Weyl Group Action*

**Abstract: **Let G be a semisimple group, for example, G = SL_n. One pervasive theme in representation theory is recovering information about representations of Lie(G) from a maximal torus T in G (for example, T may be identified with the diagonal matrices of SL_n) and its natural action by the Weyl group W := N_G(T)/T. In this talk, we will explore historical incarnations of this theme--specifically, finite dimensional Lie(G) representations and the study of the BGG category O--and then discuss a recent theorem which identifies a "varying central character" version of category O with sheaves on a space determined by the action of W on T. No prior knowledge of representation theory will be assumed.

## Student/Postdoc Working Geometry Seminar

**Time: ** 10:00PM - 11:00PM

**Location: ** zoom

**Speaker: **A. Harper, TAMU

**Title: ***Def theory: the road to stacks*