Events for 04/20/2018 from all calendars

Newton-Okounkov Bodies

Time: 1:00PM - 2:30PM

Location: BLOC 624

Speaker: Xiaoxian Tang, Texas A&M University

Title: A family of quasisymmetric models

Mathematical Physics and Harmonic Analysis Seminar

Time: 1:50PM - 2:50PM

Location: BLOC 628

Speaker: David Borthwick, Emory University

Title: Distribution of Resonances for Hyperbolic Surfaces

Abstract: For non-compact hyperbolic surfaces, the appropriate generalization of the eigenvalue spectrum is the resonance set, the set of poles of the resolvent of a meromoprhic continuation of the Laplacian. Hyperbolic surfaces serve as a model case for quantum theory when the underlying classical dynamics is chaotic. In this talk I’ll explain how the resonances are defined and discuss our current understanding of their distribution. I’ll introduce some conjectures inspired by the physics of quantum chaotic systems, and discuss numerical evidence for these conjectures and the partial progress that has been made recently.

Algebra and Combinatorics Seminar

Time: 3:00PM - 4:00PM

Location: BLOC 628

Speaker: Aleksandra Sobieska, Texas A&M University

Title: Counterexamples for Cohen-Macaulayness

Abstract: Let L in Z^n be a lattice, I its corresponding lattice ideal, and J the toric ideal arising from the saturation of L. We produce infinitely many examples, in every codimension, of pairs I,J where one of these ideals is Cohen-Macaulay but the other is not.

Geometry Seminar

Time: 4:00PM - 5:00PM

Location: BLOC 628

Speaker: F. Gesmundo, U. Cophenhagen

Title: Cactus rank and multihomogeneous polynomials

Abstract: The standard notion of matrix rank has several generalizations in algebraic geometry. Classical examples are Waring rank for homogeneous polynomials, tensor rank and in general X-rank with respect to an algebraic variety X. One additional generalization, of a more algebraic nature, is cactus rank, defined for every (smooth) algebraic variety and studied in the recent years in the settings of homogeneous polynomials and tensors. In this seminar, I will introduce cactus rank and present some of its features. In particular, we will see that whereas cactus rank presents a strong barrier in the study of other notions of rank, some of its characteristics are of great help in determining Waring rank and more generally partially symmetric rank in the tensor setting.