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Events for March 24, 2017 from General and Seminar calendars

Mathematical Physics and Harmonic Analysis Seminar

Time: 1:50PM - 2:50PM

Location: BLOC 628

Speaker: Peter Hintz, University of California, Berkeley

Title: Non-linear stability of Kerr-de Sitter black holes

Abstract: I will explain some ideas behind the proof of the stability of the Kerr-de Sitter family of black holes as solutions of the initial value problem for the Einstein vacuum equations with positive cosmological constant, for small angular momenta but without any symmetry assumptions on the initial data. I will explain the general framework which enables us to deal systematically with the diffeomorphism invariance of Einstein's equations, and thus how our solution scheme finds a suitable (wave map type) gauge within a carefully chosen finite-dimensional family of gauges; I will also address the issue of finding the mass and the angular momentum of the final black hole. This talk is based on joint work with András Vasy.

Banach Spaces Seminar

Time: 3:00PM - 4:00PM

Location: BLOC 220

Speaker: Petros Valettas, University of Missouri

Title: Variance estimates and Dvoretzky's theorem

Abstract: Abstract. The concentration of measure implies that for any norm on ℝn there exist many subspaces on which the restriction of the norm has very small distortion and whose dimension depends on the oscillations of the norm in the unit sphere of the ambient space. In this talk we will explain how the fluctuations of the norm can quantify the tightness of this phenomenon. For this end we will present a variance-sensitive small deviation inequality for convex functions of gaussian vectors. Time permitting we will show applications of the latter to the asymptotic theory of normed spaces. (Joint work with G. Paouris).

Algebra and Combinatorics Seminar

Time: 3:00PM - 3:50PM

Location: BLOC 628

Speaker: Xingwei Wang , Nankai University and Texas A&M University

Title: Infinite log-monotonicity and finite difference of combinatorial sequences

Abstract: Log-concavity and log-convexity of combinatorial sequences is related with unimodality of combinatorial sequences, real rootedness of polynomials and asymptotically normal distribution of combinatorial sequence. In this talk, we will introduce the notion of infinitely log-monotonic sequences originated from complete monotonic functions and show that some log-behaviors of combinatorial sequences can be deduced from this property. We will show many combinatorial sequence satisfying this property. Especially, we will discuss the finite difference of the logarithms of the partition function and the overpartition function.

Geometry Seminar

Time: 4:00PM - 5:00PM

Location: BLOC 628

Speaker: Robert Williams, TAMU

Title: An introduction to convex neural codes

Abstract: The brain encodes spatial structure via special neurons called place cells which are associated with convex regions of space. We seek to answer the decoding problem that arises from this situation: knowing only the firing pattern of neurons, how can we tell if it corresponds to convex regions? We will introduce tools from algebra and geometry and show how they can be used to determine if a given neural code can arise from place cells. This talk is a practice talk for a job talk.