# Events for September 29, 2017 from General and Seminar calendars

## Working Seminar on Quantum Computation and Quantum Information

Time: 10:30AM - 11:30AM

Location: BLOC 628

Speaker: Michael Brannan , TAMU

Title: Introduction and organizational meeting

## Mathematical Physics and Harmonic Analysis Seminar

Time: 1:50PM - 2:50PM

Location: BLOC 628

Speaker: Gerardo Mendoza, Temple University

Title: Free real actions, invariant CR structures, hypoellipticity, and Kodaira's vanishing theorem (joint with Several Complex Variables Seminar)

Abstract: Suppose M is a compact CR manifold with a nowhere vanishing real transverse vector field T that preserves the structure and admits an invariant metric which is Hermitian on the CR structure. Then -iT commutes with the Laplacians of the dee-bar complex and defines a selfadjoint operator on the kernel, H^q, of the Laplacian in each degree q with discrete spectrum without finite points of accumulation. Assuming non-degeneracy of the Levi form, we prove that only finitely many eigenvalues of -iT lie on the positive (or negative, depending on q and the signature of the Levi form) real axis. Finiteness of spectrum on one side or the other of 0 is strongly related to Kodaira's vanishing theorem.

## Several Complex Variables Seminar

Time: 1:50PM - 2:50PM

Location: BLOC 628

Speaker: Gerardo Mendoza, Temple University

Title: TBA (joint with MPHA Seminar)

## Noncommutative Geometry Seminar

Time: 2:00PM - 3:00PM

Location: *BLOC 220*

Speaker: Sherry Gong, Massachusetts Institute of Technology

Title: Marked link invariants: Khovanov, instanton, and binary dihedral invariants for marked links

Abstract: We introduce a version of Khovanov homology for alternating links with marking data, $\omega$, inspired by instanton theory. We show that the analogue of the spectral sequence from Khovanov homology to singular instanton homology (Kronheimer and Mrowka, \textit{Khovanov homology is an unknot-detector}) collapses on the $E_2$ page for alternating links. We moreover show that the Khovanov homology we introduce for alternating links does not depend on $\omega$; thus, the instanton homology also does not depend on $\omega$ for alternating links. Finally, we study a version of binary dihedral representations for links with markings, and show that for links of non-zero determinant, this also does not depend on $\omega$. (* Note the special time and room.)

## Algebra and Combinatorics Seminar

Time: 3:00PM - 3:50PM

Location: BLOC 117

Speaker: Sarah Witherspoon , Texas A&M University

Title: Algebraic deformation theory and the structure of Hochschild cohomology

Abstract: Some questions about deformations of algebras can be answered by using Hochschild cohomology, and in particular by using its Lie/Gerstenhaber brackets. Until very recently there was no independent description of this Lie structure for an arbitrary resolution, a big disadvantage both theoretically and computationally. In this talk, we will first introduce Hochschild cohomology and explain its role in algebraic deformation theory. We will then summarize recent progress by several mathematicians, focusing on examples.

## Geometry Seminar

Time: 4:00PM - 5:00PM

Location: BLOC 628

Speaker: JM Landsberg, TAMU

Title: Quantum max flow v. quantum min cut and the geometry of matrix product states

## Linear Analysis Seminar

Time: 4:00PM - 5:00PM

Location: BLOC 220

Speaker: Scott LaLonde, University of Texas at Tyler

Title: Fell bundles: Unifying C*-algebras associated to groupoids

Abstract: Fell bundles provide one with an abstract notion of groupoid actions on C*-algebras. As a result, they provide a unifying framework in which to study many of the C*-algebras that are often associated to groupoids, including the groupoid C*-algebra, groupoid crossed products, and twisted versions of both constructions. We will discuss some recent work on Fell bundles, including a powerful stabilization result of Ionescu, Kumjian, Sims, and Williams that relates an arbitrary Fell bundle to a canonical groupoid crossed product. We focus on some consequences of this theorem in the context of nuclearity and exactness for Fell bundle C*-algebras, as well as some connections to exact groupoids and groupoid extensions.