Events for 04/28/2025 from all calendars

Geometry Seminar

Time: 3:00PM - 3:50PM

Location: Bloc 302

Speaker: Emily McMillon, Rice University

Title: Building Codes from Group Testing Matrices

Abstract: Parity-check codes are a class of linear codes defined by their parity-check matrices. Disjunct matrices are used extensively in combinatorial group testing but were not previously well-studied as parity-check matrices for binary linear codes. We will give results on code parameters including rate, distance, and girth for both codes from general disjunct matrices and codes obtained via the Kautz-Singleton construction for superimposed codes. The talk will be accessible to those without previous knowledge of parity-check codes and combinatorial group testing.

Applied Math Seminar

Time: 4:00PM - 5:00PM

Location: Zoom

Speaker: Christoph Borgers, Tufts University, Medford, MA

Title: The yard-sale convergence theorem

Abstract: Suppose n identical agents engage in a sequence of trades. Each trade involves a random pair of agents, and as a result of the trade, one agent gains some amount of wealth, and the other loses the same amount. The total amount of wealth is conserved, call it W. The amount of wealth transferred is a small fraction of the poorer trading partner’s pre-trade wealth, so nobody ever goes bankrupt. The direction of wealth transfer is random with both possibilities equally likely. The yard-sale convergence theorem states that with probability 1, the wealth of one agent will converge to W, and the wealth of all others will therefore converge to 0. For short, randomness that is fair in expectation inescapably leads to total oligarchy. This was first observed by Anirban Chakraborti 25 years ago. It is an immediate consequence of the martingale convergence theorem. However, I will give a more elementary proof, using nothing heavier than the Borel-Cantelli lemma, of a stronger result. This is joint work with Claude Greengard.

Student/Postdoc Working Geometry Seminar

Time: 4:00PM - 5:00PM

Location: BLOC 302

Speaker: T. Mandziuk, Texas A&M

Title: Border rank lower bounds via deformation theory

Math Club Seminar : Platonic solids in the next dimension

Time: 7:00PM - 8:00PM

Location: BLOC 306

Speaker: Dr. Frank Sottile - TAMU

Description: We will discuss the six regular solids in dimension 4, including building a projection of the 4-cube, along with viewing some other models. Here is a visual abstract, and a guide to building the 4-cube. More Info: There will be refreshments provided, and the meeting will satisfy credit for MATH 170. We also have a Math Club Discord which contains info about our meetings and may also be used to contact our officers and other members! You can sign up at this link here. Also the meeting will be preceded by officer elections at 6:45pm.