Past Year Events of the Week

Week of March 3 - February 27, 2017

*Friday, March 3*

**Topic**

*Thursday, March 2*

**Topic**

*Thursday, March 2*

**Topic**

*Wednesday, February 1*

**Topic**

*Tuesday, February 28*

**Mardi Gras Break**

All University Offices will be closed

Have a safe Holiday

*Monday, February 27*

**Mardi Gras Break**

All University Offices will be closed

Have a safe Holiday

**Week of February 24 - February 20, 2017**

*Friday, February 24*

**Topic**

*Thursday, February 23*

## Colloquium

**Why is the ergodic theory of stochastic PDEs different?**

*Thursday, February 23*

**Topic**

*Wednesday, February 22*

**Topic**

*Tuesday, February 21*

**Secret Meeting of the L5 Society**

*Monday, February 20*

**Topic**

**Week of February 17 - February 13, 2017**

*Friday, February 17*

**Topic**

*Thursday, February 16*

## Algebra and Combinatorics Seminar

**Classification of spherical diagonal actions of reductive groups, Part II.**

*Wednesday, February 15*

**Continuum approximation of invasion probabilities for stochastic population models**

In this talk, we compare popular continuum approximations for the invasion probability to its exact solution. In particular, methods known as "Diffusion (or Stochastic Differential Equation) Approximation" and "Exponential Approximation" are derived. We find analytical expressions for these approximations in the large population limit and then use numerical methods to evaluate the performance of the approximation methods for finite populations. Interestingly we find that the diffusion approximation fails to obtain the correct large population limit, but can perform well for small populations that experience near critical dynamics. The exponential approximation obtains the right large population limit in the supercritical regime, but fails to capture nonmontonic characteristics of the invasion probability for small to intermediate sized populations.

*Wednesday, February 14*

## GRAD STUDENT COLLOQUIUM

**Lasso, Group Lasso, and SLOPE**

From linear regression, I will introduce the penalty method such as ridge method and lasso method. However, in some cases, the variates have strong correlation with each other, then we can use the group lasso. After that, I will talk about SLOPE(sorted L-One Penalty Estimation), which is method similar to the lasso method and consider the false discovery rate as the criteria.

*Tuesday, February 14*

## COFFEE AND DISCUSSION: “Finding opportunities for conferences, workshops, etc”

**Location: Dinwiddie Hall 102**

*Monday, February 13*

## Special Mathematical Biology seminar

**Diabetes: One Disease, Many Paths**

**Week of February 10 - February 6, 2017**

*Friday, February 10*

**Topic**

*Thursday, February 9*

## Colloquium

**Global Regularity v.s. Finite Time Blowup for Compressible Euler Equations**

*Wednesday, February 9*

## Algebra and Combinatorics Seminar

**Classification of spherical diagonal actions of reductive groups**

*Wednesday, February 8*

## Probability and Statistics

**Scalings and saturation in infinite-dimensional control problems with applications to stochastic partial differential equations.**

*Tuesday, February 7*

## Graduate Student Colloquium

**Poincare Duality With Local Coecients**

*Monday, February 7*

## TULANE AWM/AMS STUDENT CHAPTERS

**Introduction to Riemannian Geometry**

*Monday, February 6*

**Topic**

Week of February 3 - January 30, 2017

*Friday, February 3*

**Topic**

*Thursday, February 2*

## Colloquium

**Limit Shapes for Rational Functions**

Robin PemantleUniversity of Pennsylvania (host mahir can)

**Time: 3:30**

*Thursday, February 2*

## Algebra and Combinatorics Seminar

**Introduction to the Hodge Conjecture (part 2)**

*Wednesday, February 1*

**Topic**

*Friday, February 31*

## Graduate Student Colloquium

**Some algebraic properties of toric edge rings**

*Tuesday, January 31*

## AWM / AMS

**Biofluids of reproduction: oscillators, viscoelastic networks and sticky situations.**

*Monday, January 30*

**Topic**

**Week of January 27 - January 23, 2017**

*Friday, January 27*

**Topic**

*Thursday, January 26*

## Algebra and Combinatorics Seminar

**Introduction to the Hodge Conjecture**

*Wednesday, January 25*

**Topic**

*Tuesday, January 24*

## Graduate Student Colloquium

**The Method of Brackets**

*Monday, January 23*

**Topic**

**Week of January 20 - January 16, 2017**

*Friday, January 20*

**Topic**

*Thursday, January 20*

**Sixth Annual Winter Workshop on Neuromechanics and Dynamics of Locomotion**

Location: Lavin Bernick Center for University Life (building 29) - Kendall Cram Room

*Thursday, January 19*

**Sixth Annual Winter Workshop on Neuromechanics and Dynamics of Locomotion**

Location: Lavin Bernick Center for University Life (building 29) - Kendall Cram Room

*Thursday, January 19*

**Topic**

*Wednesday, January 18*

**Topic**

*Tuesday, January 17*

**Topic**

*Monday, January 16*

**Martin Luther King Day**

Week of March 3 - February 27, 2017

**Speaker - Institution
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**Speaker - Institution
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All University Offices will be closed

Have a safe Holiday

All University Offices will be closed

Have a safe Holiday

**Speaker - Institution
**

**Abstract:
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**Location:
**

**Time:**

**Jonathan Mattingly - Duke (HOST: Nathan Glatt-Holtz and Scott McKinley)
**

**Abstract:
**

Ergodicity is one of the fundamental questions for a stochastic dynamical system, ensuring the convergence of long time averages of observable quantities to a statistical steady state independent of the initial condition.

I will explore why the ergodic theory of stochastic PDEs is different and how it underlines the basic difference between ODEs and PDEs. I will start at the beginning giving a crash course on the basic elements needed to prove an ergodic result. We will come to understand why sometimes ergodicity can be easy for hard PDEs. Time permitting I will touch on hypoellipticity in infinite dimensions and singular PDEs.

**Location: Dimwiddie 102
**

**Time: 3:30**

**Speaker - Institution
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**Abstract:
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**Location:
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**Speaker - Institution
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**Time:**

**Kristi Vandusen and Padi Fuster - Tulane University
**

**Abstract:
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**Secret Meeting of the L5 Society
**

**Location: Stanley Thomas 316
**

**Time: 4:15**

**Speaker - Institution
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**Abstract:
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**Location:
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**Time:**

**Speaker - Institution
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**Abstract:
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**Location:
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**Time:**

**Mahir Bilen Can - Tulane University
**

**Abstract:
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**Location: Gibson Hall 400A
**

**Time: 12:45**

**Rebecca Borchering - University of Florida
**

**Abstract:
**

In this talk, we compare popular continuum approximations for the invasion probability to its exact solution. In particular, methods known as "Diffusion (or Stochastic Differential Equation) Approximation" and "Exponential Approximation" are derived. We find analytical expressions for these approximations in the large population limit and then use numerical methods to evaluate the performance of the approximation methods for finite populations. Interestingly we find that the diffusion approximation fails to obtain the correct large population limit, but can perform well for small populations that experience near critical dynamics. The exponential approximation obtains the right large population limit in the supercritical regime, but fails to capture nonmontonic characteristics of the invasion probability for small to intermediate sized populations.

**Location: Gibson 126
**

**Time: 3:00**

**Lin Li - Tulane University
**

**Abstract:
**

From linear regression, I will introduce the penalty method such as ridge method and lasso method. However, in some cases, the variates have strong correlation with each other, then we can use the group lasso. After that, I will talk about SLOPE(sorted L-One Penalty Estimation), which is method similar to the lasso method and consider the false discovery rate as the criteria.

**Location: Stanley Thomas 316
**

**Time: 4:15**

**Tulane AWM/AMS Student Chapter present:**

**Speaker - Institution
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**Abstract:**

**Time: 2:00**

**Dr. Arthur Sherman - National Institutes of Health
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**Abstract:
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**Location: Stanley Thomas 316
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**Time: 3:00**

**Speaker - Institution
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**Abstract:
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**Location:
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**Time:**

**Prof. Ronghua Pan - Georgia Tech (host Kun Zhao)
**

**Abstract:
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As one of the oldest nonlinear PDE systems, the compressible Euler equations has been studied by many outstanding mathematicians. However, some basic questions, such as the global existence of classical solution v.s. finite time blowup, are still open even in one space dimension. In this lecture, we will report our recent progress in this direction, including a complete understanding on isentropic flows, and a refreshed understanding on general adiabatic flows. This lecture is based on joint works with H. Cai, G. Chen, S. Zhu, and Y. Zhu.

**Location: Dinwiddie 102
**

**Time: 3:30**

**Mahir Bilen Can - Tulane University
**

**Abstract:
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In this talk we present our recent progress on the diagonal actions of a reductive groups on product varieties of the form X_1 x X_2, where X_1 is a symmetric space and X_2 is a partial flag variety. In particular, we classify all such actions.

**Location: Gibson Hall 400A
**

**Time:12:45**

**David Herzog - Institution
**

**Abstract:
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**Location: Gibson Hall 126
**

**Time: 3:00**

**Fang Sun - Tulane University
**

**Abstract:
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**Location: Stanley Thomas 316
**

**Time: 4:15**

**DR. DAGANG YANG - Tulaner - Institution
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**Abstract:
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This talk is a brief introduction to Riemannian geometry. Namely, I will explain what is a Riemannian manifold, why should one be interested in Riemannian geometry, the meaning of the sign of the sectional curvature, and some well-known open problems in Riemannian geometry.

**Location: Dimwiddie Hall 102
**

**Time: 2:00**

**Speaker - Institution
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**Abstract:
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**Location:
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**Time:**

Week of February 3 - January 30, 2017

**Speaker - Institution
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**Abstract:
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**Location:
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**Time:**

Robin Pemantle

**Abstract:**

**Exact enumeration in probability and combinatorics often leads to rational generating functions. These, in turn, lead to limit shapes, often more exotic than the generic Gaussian shape arising from a Central Limit Theorem. This motivates the study of the asymptotics of the coefficients of a rational power series**

** F(Z) = P(Z) / Q(Z) = sum_R a_R Z^R
**

**where Z = (z_1, ... , z_d) and R = (r_1, ..., r_d) are d-tuples. Estimating a_R from P and Q is both a theoretical problem and a problem in effective computation. I will discuss what we know about how to read limit shape behavior from P and Q (mostly from Q). The examples in the pictures will all be explained.
**

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**Location: Dinwiddie 102
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**Al Vitter - Tulane University
**

**Abstract:
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This will be a continuation of my first talk. I will state the Hodge Conjecture and then talk about some aspects that show its subtlety and importance. The Hodge Conjecture concerns smooth (non-singular) complex projective varieties. It relates the purely algebraic structure of the variety to its topological/complex-analytic structure via its cohomology groups. I will begin by discussing in a relatively untechnical way, some of the mathematics needed to state clearly the Hodge Conjecture.

**Location: Gibson 400A**

**Time: 1:00**

**Speaker - Institution
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**Abstract:
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**Location:
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**Time:**

**Slivi Beyarslan - Tulane University
**

**Abstract:
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**Location: Stanley Thomas 316
**

**Time: 4:15**

**Dr. Lisa Fauci - Tulane University
**

**Abstract:
**

From fertilization to birth, successful mammalian reproduction relies on interactions of elastic structures with a fluid environment. Sperm flagella must move through cervical mucus to the uterus and into the oviduct, where fertilization occurs. In fact, some sperm may adhere to oviductal epithelia, and must change their pattern of oscillation to escape. In addition, coordinated beating of oviductal cilia also drives the flow. Sperm-egg penetration, transport of the fertilized ovum from the oviduct to its implantation in the uterus and, indeed, birth itself are rich examples of elasto-hydrodynamic coupling.

We will discuss successes and challenges in the mathematical and computational modeling of the biofluids of reproduction. In addition, we will present reduced models that evoke intriguing questions in fundamental fluid dynamics.

**Location: Dinwiddie 102
**

**Time: 2:00**

**Speaker - Institution
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**Abstract:
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**Speaker - Institution
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**Location:
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**Time:**

**Al Vitter - Tulane University
**

**Abstract:
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This will be the first of probably 2 talks. The Hodge Conjecture concerns smooth (non-singular) complex projective varieties. It relates the purely algebraic structure of the variety to its topological/complex-analytic structure via its cohomology groups. I will begin by discussing in a relatively untechnical way, some of the mathematics needed to state clearly the Hodge Conjecture. Then I will concentrate on some aspects that bring out (hopefully) the subtlety and importance of the conjecture.

**Location: Gibson Hall 400A
**

**Time: 4:00**

**Speaker - Institution
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**Abstract:
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**Location:
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**Time:**

**Victor H. Moll - Tulane University
**

**Abstract:**

**
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**Location: Stanley Thomas 316
**

**Time: 4:30**

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**Speaker - Institution
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Location: Lavin Bernick Center for University Life (building 29) - Kendall Cram Room

Location: Lavin Bernick Center for University Life (building 29) - Kendall Cram Room

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Mathematics Department, 424 Gibson Hall, New Orleans, LA 70118 504-865-5727 math@math.tulane.edu