Events for 10/09/2020 from all calendars

Student Working Seminar in Groups and Dynamics

Time: 11:00AM - 12:00PM

Location: Zoom

Speaker: James O'Quinn

Title: Ergodic theorems and amenability

Abstract: Ergodic theorems are one of the main technical cornerstones of ergodic theory, which is the study of dynamical systems from a measurable perspective. Roughly speaking, an ergodic theorem provides a relation between averaging a function over the dynamics and and averaging a function over the space for ergodic systems. Thinking of a dynamical system as a group action on a measure space, the kind of averaging necessary for ergodic theorems to hold happens readily for actions of the integers, but may not be available for other groups. However, amenable groups provide the type of averaging we need. During this talk, I will introduce some of the main ideas in ergodic theory, focusing on the ergodic theorems. I will also relate this to amenable groups, which are objects of great interest in current research and permeate many areas of analysis. No background in dynamics or group theory is assumed for this talk. Newcomers and those with a passing interest in this area are especially encouraged to attend.

Spectral Theory Reading Seminar

Time: 11:00AM - 11:50AM

Location: Zoom

Title: Kickoff meeting

Algebra and Combinatorics Seminar

Time: 3:00PM - 4:00PM

Location: Zoom

Speaker: Cvetelina Hill, Georgia Tech

Title: Tropical convex hulls of polyhedral sets

Abstract: This talk is based on joint work with Sala Lamboglia and Faye Pasley Simon. During the first part of the talk we will focus on the tropical convex hull of convex sets and polyhedral complexes. We will introduce results on the tropical convex hull of a line segment and a ray, show that for sets in two dimensions tropical convex hull and ordinary convex hull commute, and give a characterization of tropically convex polyhedra. In the second part of the talk we will use these results to show that the dimension of a tropically convex fan depends on the coordinates of its rays and give a lower bound on the degree of a fan tropical curve using only tropical techniques. The talk will be based on the work in this paper: https://arxiv.org/abs/1912.01253v2.

Open Teaching with Technology Forum

Time: 3:30PM - 5:00PM

Location: Zoom

Speaker: Vanessa Coffelt

Description: Join Zoom Meeting: https://tamu.zoom.us/j/93142718312?pwd=c2x5Zm5RZWdheEJ4SU40N3VYMlFpdz09 Meeting ID: 931 4271 8312

Geometry Seminar

Time: 4:00PM - 4:50PM

Location: zoom

Speaker: Leon Zhang, UC Berkeley

Title: Tropical geometry and applications

Abstract: I will describe results from two recent projects in tropical geometry with relevance in applications. In the first half, I will introduce and give several characterizations for flags of tropical linear spaces, in analogy to Speyer's results for tropical linear spaces. In the second half, I will discuss ongoing work relating tropical fewnomials, vertex bounds of Minkowski sums, and linear regions of maxout neural networks.