# Events for 01/27/2022 from all calendars

## Number Theory Seminar

**Time: ** 10:00AM - 11:00AM

**Location: ** BLOC 302

**Speaker: **Matt Young, Texas A&M University

**Title: ***TBA*

## Colloquium - Visu Makam

**Time: ** 11:30AM - 12:30PM

**Location: ** ZOOM

**Speaker: **Visu Makam, University of Melbourne, Australia

**Description: **

**Title:** Interactions between invariant theory and complexity theory

**Abstract:** Invariant theory and complexity theory are two fundamental subjects in algebra and theoretical computer science respectively. The two subjects have found common ground in the past two decades due to some spectacular discoveries that place invariant theory and representation theory at the forefront of some of the central open problems in complexity theory such as identity testing and even the celebrated P vs NP problem. In this talk, I will present my perspective of this young and rapidly developing field. I will emphasize new research directions in invariant theory motivated by investigations in complexity theory and how various results in invariant theory can inform and evolve our understanding of complexity theory. I will draw upon results from joint works with several collaborators and showcase some results with a view towards the future of the subject.

## Colloquium - Yuwen Li

**Time: ** 4:00PM - 5:00PM

**Location: ** BLOC 117

**Speaker: **Yuwen Li, Pennsylvania State University

**Description: **

**Title:** Preconditioning in H(curl) and H(div)

**Abstract: **Preconditioning is widely used for efficiently solving large-scale systems of linear equations. In the first part of my talk, I will present a novel application of preconditioning and derive a posteriori error estimates of finite element methods in H(curl) and H(div) using preconditioning theory. In the second part, I will show new user-friendly preconditioners for solving discrete H(curl) and H(div) systems on triangulated surfaces. Part of this talk is based on joint work with Ludmil Zikatanov.