Topology Seminar
Seminar website

Posted August 24, 2017

3:30 pm - 4:30 pm Lockett 233
Mike Wong, Louisiana State University

TBD

Applied Analysis Seminar
Questions or comments?

Posted August 25, 2017

Last modified September 8, 2017

Changfeng Gui, University of Texas at San Antonio

The Sphere Covering Inequality and its applications

In this talk, I will introduce a new geometric inequality: the Sphere Covering Inequality. The inequality states that the total area of two {it distinct} surfaces with Gaussian curvature less than 1, which are also conformal to the Euclidean unit disk with the same conformal factor on the boundary, must be at least $4 pi$. In other words, the areas of these surfaces must cover the whole unit sphere after a proper rearrangement. We apply the Sphere Covering Inequality to show the best constant of a Moser-Trudinger type inequality conjectured by A. Chang and P. Yang. Other applications of this inequality include the classification of certain Onsager vortices on the sphere, the radially symmetry of solutions to Gaussian curvature equation on the plane, classification of solutions for mean field equations on flat tori and the standard sphere, etc. The resolution of several open problems in these areas will be presented. The talk is based on joint work with Amir Moradifam from UC Riverside.

Colloquium
Questions or comments?

Posted August 22, 2017

Last modified August 27, 2017

Hongyu He, Department of Mathematics, LSU

Branching Laws and Interlacing Relation

Abstract: Let $H$ be a subgroup of a compact group $G$. Then any irreducible unitary representation of $G$, when restricted to $H$, decomposes into a direct sum of irreducible representations of $H$. A description of such a decomposition is often called a branching law. They are important in harmonic analysis, quantum mechanics and number theory. In this talk, I shall discuss the branching laws of the discrete series of the noncompact unitary groups and the recent progress towards the local Gan-Gross-Prasad conjectures. Discrete series representations were classified by Harish-Chandra in the sixties and played a fundamental role in Langland's program.

Computational Mathematics Seminar

Posted August 22, 2017

3:30 pm - 4:30 pm 1034 Digital Media Center
Yangyang Xu, University of Alabama

Primal-dual methods for affinely constrained problems

Abstract: Optimization has been applied in many areas including engineering, statistics, finance, and data sciences. Modern applications often have rich structure information. Traditional methods like projected subgradient and the augmented Lagrangian can be used, but they do not utilize structures of the problems and thus are not so efficient. This talk will focus on convex optimization problems with affine constraints. The first part assumes two-block structure on the problem and presents the alternating direction method of multipliers (ADMM) and its accelerated variant. With strong convexity on one block variable, the ADMM can be accelerated from O(1/k) rate to O(1/k^2). Numerical results will be given to demonstrate the improved speed. In the second part, I will present a novel primal-dual block update method for a multi-block (at least three blocks) problem. Existing works have shown that directly extending two-block ADMM to multi-block problems may diverge. To guarantee convergence, either strong assumptions are made or updating order of the blocks has to be changed. Our method uses a simple randomization technique on choosing block variables, and it enjoys O(1/k) ergodic convergence rate and also global convergence in probability. In addition, by choosing a few blocks every time and using Jacobi-type update, the method enables parallel computing with guaranteed convergence. Numerical experiments will be shown to demonstrate its efficiency compared to other methods.

Informal Topology Seminar
Questions or comments?

Posted August 23, 2017

Last modified September 11, 2017

Yu-Chan Chang, Louisiana State University

Introduction to bounded cohomology of discrete groups

Abstract: In this introductory talk, we will focus on bounded cohomology of discrete groups with real or integer coefficient. I will talk about the bounded cohomology of Gromov hyperbolic groups and amenable groups. Also, we will discuss the comparison map, which is the map from the bounded cohomology to the usual cohomology.

Topology Seminar
Seminar website

Posted August 24, 2017

3:30 pm - 4:30 pm Lockett 233
John Etnyre, Georgia Institute of Technology

TBD

Colloquium
Questions or comments?

Posted August 25, 2017

Last modified September 19, 2017

John Etnyre, Georgia Institute of Technology

Curvature and contact topology

Abstract: Contact geometry is a beautiful subject that has important interactions with topology in dimension three. In this talk I will give a brief introduction to contact geometry and discuss its interactions with Riemannian geometry. In particular I will discuss a contact geometry analog of the famous sphere theorem and more generally indicate how the curvature of a Riemannian metric can influence properties of a contact structure adapted to it. This is joint work with Rafal Komendarczyk and Patrick Massot.

Computational Mathematics Seminar

Posted September 14, 2017

4:15 pm - 5:00 pm 1034 Digital Media CenterComputational Mathematics Presentations

Informal Topology Seminar
Questions or comments?

Posted August 23, 2017

10:30 am - 12:00 pm Lockett 233
Kent Vashaw, Louisiana State University

TBD

Applied Analysis Seminar
Questions or comments?

Posted August 9, 2017

Last modified September 3, 2017

Giles Auchmuty, University of Houston

The SVD of the Poisson kernel

Computational Mathematics Seminar

Posted August 22, 2017

Last modified September 14, 2017

Xiang Xu, Old Dominion University

Eigenvalue preservation for the Beris-Edwards system modeling nematic liquid crystals

Abstract: The Beris-Edward equations are a hydrodynamic system modeling nematic liquid crystals in the setting of Q-tensor order parameter. Mathematically speaking it is the incompressible Navier-Stokes equations coupled with a Q-tensor equation of parabolic type. In this talk we first consider the simplified Beris-Edward system that corresponds to the co-rotational case, and study the eigenvalue preservation property for the initial Q-tensororder parameter. Then we show that for the full system that relates to the non-rotational case, this property is not valid in general.

Informal Topology Seminar
Questions or comments?

Posted August 23, 2017

10:30 am - 12:00 pm Lockett 233
Rima Chatterjee, Louisiana State University

TBD

Applied Analysis Seminar
Questions or comments?

Posted August 7, 2017

Last modified September 3, 2017

Keng Deng, University of Louisiana at Lafayette

Global existence and blow-up for nonlinear diffusion equations with boundary flux governed by memory

In this talk, we introduce the study of global existence and blow-up in finite time for nonlinear diffusion equations with flux at the boundary governed by memory. Via a simple transformation, the memory term arises out of a corresponding model introduced in previous studies of tumor-induced angiogenesis. The study is also in the spirit of extending work on models of the heat equation with local, nonlocal, and delay nonlinearities present in the boundary flux. Specifically, we establish an identical set of necessary and sufficient conditions for blow-up in finite time as previously established in the case of local flux conditions at the boundary.

Informal Topology Seminar
Questions or comments?

Posted August 25, 2017

10:30 am - 12:00 pm Lockett 233
Sudipta Ghosh, Louisiana State University

TBD

Applied Analysis Seminar
Questions or comments?

Posted August 25, 2017

Last modified September 3, 2017

Ryan Hynd, University of Pennsylvania

TBA

Topology Seminar
Seminar website

Posted August 27, 2017

3:30 pm - 4:30 pm Lockett 233
Robin Koytcheff, University of Louisiana, Lafayette

TBD

Applied Analysis Seminar
Questions or comments?

Posted September 13, 2017

2:30 pm - 3:20 pm Lockett 233
Jiahong Wu, Oklahoma State University

Partial differential equations related to fluids with partial or fractional dissipation

There have been substantial recent developments on several partial differential equations from fluid dynamics with partial or fractional dissipation. This talk summarizes results on the global existence and regularity problem for the 3D Navier-Stokes equations with partial hyperdissipation, the surface quasi-geostrophic equation, the 2D Boussinesq equations with partial or fractional dissipation and the 2D magnetohydrodynamic equations with partial or fractional dissipation.

Computational Mathematics Seminar

Posted August 22, 2017

3:30 pm - 4:30 pm 1034 Digital Media Center
Joscha Gedicke, Universitaet Wien

TBA

Applied Analysis Seminar
Questions or comments?

Posted August 15, 2017

Last modified September 3, 2017

Kun Zhao, Tulane University

TBA

Topology Seminar
Seminar website

Posted September 13, 2017

3:30 pm - 4:30 pm Lockett 233
Yilong Wang, The Ohio State University

TBD

Algebra and Number Theory Seminar
Questions or comments?

Posted September 9, 2017

3:00 pm - 3:50 pm
Anna Romanov, University of Utah

TBD

Computational Mathematics Seminar

Posted August 23, 2017

3:30 pm - 4:30 pm 1034 Digital Media Center
Daniele Venturi, University of California Santa Cruz

TBA

Applied Analysis Seminar
Questions or comments?

Posted August 15, 2017

Last modified September 3, 2017

Zhifu Xie, University of Southern Mississippi

TBA

Informal Topology Seminar
Questions or comments?

Posted August 23, 2017

10:30 am - 12:00 pm Lockett 233
Rob Quarles, Louisiana State University

TBD

Frontiers of Scientific Computing Lecture Series

Posted August 22, 2017

11:00 am - 12:00 pm 1034 Digital Media Center
Xiao-Chuan Cai, University of Colorado Boulder

TBA

Algebra and Number Theory Seminar
Questions or comments?

Posted August 31, 2017

3:00 pm - 3:50 pm
Yifan Yang, National Taiwan University

TBD

Computational Mathematics Seminar

Posted September 12, 2017

3:30 pm - 4:30 pm 1034 Digital Media Center
Shawn Walker, LSU

TBA

Colloquium
Questions or comments?

Posted September 1, 2017

Last modified September 5, 2017

Yifan Yang, National Taiwan University

TBD

Algebra and Number Theory Seminar
Questions or comments?

Posted August 23, 2017

Last modified September 9, 2017

Li Guo, Rutgers University at Newark

TBD

Topology Seminar
Seminar website

Posted August 23, 2017

Last modified September 6, 2017

Shelly Harvey, Rice University

TBD