# Events for 10/25/2019 from all calendars

## Austin-TAMU Probability and Related Fields

**Time:** 09:30AM - 5:30PM

**Location:** Bloc 506A

**Description:** Austin-TAMU Probability and Related Fields: Fall 2019

The Austin-TAMU probability and Related Fields day is a twice-yearly event, alternately held at UT Austin and Texas A&M. Our fifth-ever meeting will be held at TAMU on Friday, October 25th, 2019 in the Blocker Building (room TBD) with four speakers, an open problem session, and plenty of time for discussion and collaboration. See the schedule for more details about the schedule.

All talks (including coffee and lunch) will take place in RLM. From 10am-2pm we will be in room 8.136. From 2pm-4pm we will be in room 10.176.

For those visiting from Austin, TAMU will reimburse you for gas and parking costs. Please try to car pool for both the environment and to cut costs. Deadline: Please register by October 11th. Speakers: Boris Hanin (TAMU) Hanbaek Lyu (UCLA)

**URL:** *Link*

## Probability Seminar

**Time:** 11:30AM - 12:30PM

**Location:** BLOC 628

**Speaker:** Hanbaek Lyu, UCLA

**Title:** *TBA*

**Abstract:** TBA

## Postdoc Lunch Time Talks

**Time:** 12:00PM - 12:00PM

**Location:** BLOC 220

**Speaker:** Bob Booth, Texas A&M University

**Description:**

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## Postdoc Lunch Time Talks

**Time:** 12:35PM - 12:35PM

**Location:** BLOC 220

**Speaker:** Shuang Ming, Texas A&M University

**Description:**

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## Postdoc Lunch Time Talks

**Time:** 12:55PM - 1:55PM

**Location:** BLOC 220

**Speaker:** Diane Guignard, Texas A&M University

**Description:**

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## Mathematical Physics and Harmonic Analysis Seminar

**Time:** 1:50PM - 2:50PM

**Location:** BLOC 628

**Speaker:** P. Kuchment, TAMU

**Title:** *On generic non-degeneracy of spectral edges. Discrete case*

**Abstract:** This is joint work with Frank Sottile (TAMU) and Ngoc T. Do (Missouri State U.)

An old problem in mathematical physics deals with the structure of the dispersion relation of the Schrodinger operator -Delta+V(x) in R^n with periodic potential near the edges of the spectrum, i.e. near extrema of the dispersion relation. A well known and widely believed conjecture says that generically (with respect to perturbations of the periodic potential) the extrema are attained by a single branch of the dispersion relation, are isolated, and have non-degenerate Hessian (i.e., dispersion relations are graphs of Morse functions). In particular, the important notion of effective masses hinges upon this property.

The progress in proving this conjecture has been slow. It is natural to try to look at discrete problems, where the dispersion relation is (in appropriate coordinates) an algebraic, rather than analytic, variety. Moreover, such models are often used for computation in solid state physics (the tight binding model). Alas, counterexamples showing that the genericity can fail in some discrete situations do exist.

In our work, we consider the case of a general periodic discrete operator depending polynomially on some parameters. We prove that the non-degeneracy of extrema either fails or holds for all but a proper algebraic subset of values of parameters. Thus, a random choice of a point in the parameter space will give the correct answer "with probability one". A specific example of a diatomic Z^2-periodic structure is also considered, which provides a cornucopia of examples for both alternatives, as well as a different approach to the genericity problem.

## Algebra and Combinatorics Seminar

**Time:** 3:00PM - 3:00PM

**Location:** BLOC 506A **

**Speaker:** Frank Sottile, Texas A&M University

**Title:** *Composed Schubert Problems*

## Linear Analysis Seminar

**Time:** 4:00PM - 5:00PM

**Location:** BLOC 220

**Speaker:** Jordyn Harriger, Indiana University

**Title:** *TBA*

**Abstract:** TBA