Upcoming MAMS Colloquium Series

Spring 2025

Fall 2024

4/18/2025, Friday 3:15-4:15 pm in Sears 439
Speaker: Henry Segerman (Oklahoma State University)
Title: Avoiding inessential edges
Abstract: Results of Matveev, Piergallini, and Amendola show that any two triangulations of a three-manifold with the same number of vertices are related to each other by a sequence of local combinatorial moves (namely, 2-3 and 3-2 moves). For some applications however, we need our triangulations to have certain properties, for example that all edges are essential. (An edge is inessential if both ends are incident to a single vertex, into which the edge can be homotoped.) We show that if the universal cover of the manifold has infinitely many boundary components, then the set of essential ideal triangulations is connected under 2-3, 3-2, 0-2, and 2-0 moves.
Our results have applications in veering triangulations and in quantum invariants such as the 1-loop invariant. This is joint work with Tejas Kalelkar and Saul Schleimer.

4/11/2025, Friday 3:15-4:15 pm via Zoom
Speaker: Yuexiao Dong (Temple University)
Title: On profile principal generalized linear model for sufficient dimension reduction
Abstract: As an extension of linear regression, generalized linear model (GLM) provides a flexible framework that allows the response variable to follow an exponential family distribution. The canonical link function in GLM, which maps the conditional mean of the response given the predictors to a linear combination of the predictors, is pre-determined by the response distribution. In this paper, we consider a single-index model where the conditional mean of the response is an unknown function of a linear combination of the predictors. The coefficients of the linear combination are estimated via a newly proposed sufficient dimension reduction method: principal GLM (PGLM). Based on the initial PGLM estimator, we can leverage the GLM assumption and refine estimation of the unknown link function as well as the linear combination coefficients via profiling, and we refer to the refined estimator as the profile PGLM estimator (PPGLM). Last but not least, we explore generalized partially linear single index models as well as parallel computation under this flexible PPGLM framework.

4/4/2025, Friday 3:15-4:15 pm in Sears 439
Speaker: Amy Buchmann (University of San Diego)
Title: Computational Models of Microorganism Motility
Abstract: In the field of computational biofluids, we create mathematical and computational models to study the mechanics of biological fluids within the human body, including the circulatory and respiratory systems, as well as the motility of microorganisms. The Method of Regularized Stokelets can be used to model microorganisms immersed in a viscous fluid. Using this method we can model both rigid and elastic filaments immersed in a fluid to study the coordination of flagella and cilia.

3/28/2025, Friday 3:15-4:15 pm in Sears 439
Speaker: Semyon Alesker (Tel Aviv University/ currently at Kent)
Title: The joy of computation in homotopy theory
Abstract: Valuations are finitely additive measures on convex compact sets. In the last two decades a number of structures (e.g. product and convolution) with non-trivial properties were discovered on the space of valuations. One such recently discovered property is an analogue of the classical Hodge-Riemann bilinear relations known in algebraic/Kaehler geometry. In special cases, they lead to new inequalities for convex bodies, to be discussed in the talk. No familiarity with valuations theory and algebraic/Kaehler geometry is assumed.

3/7/2025, Friday 3:15-4:15 pm in Sears 439
Speaker: Dr. Dan Isaksen (Wayne State University)
Title: The joy of computation in homotopy theory
Abstract: In part, the goal of homotopy theory is to compute algebraic invariants of topological objects. Of particular interest is the computation of homotopy groups of spheres. Like many areas of pure mathematics, machine computation can be applied to great effect in this endeavor. I will discuss the history, current state of the art, and future prospects of machine computation in homotopy theory.

1/17/2025, Friday 3-4 pm in Sears 439
Speaker: Dr. Marjorie Drake (Massachusetts Institute of Technology)
Title: Convexity in Whitney Problems
Abstract:1/17/2025, Friday. 3-4 pm in Sears 439
Speaker: Dr. Marjorie Drake (Massachusetts Institute of Technology)
Title: Convexity in Whitney Problems
Abstract: DrakeTalkAbstract