Calendar

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Today, Friday, November 6, 2026

Posted September 30, 2026

Control and Optimization Seminar Questions or comments?

10:30 am – 11:20 am Zoom: https://lsu.zoom.us/j/98176468969

Daniel Wachsmuth, University of Wuerzburg, Germany
Solution Algorithms for Nonsmooth Optimal Control Problems Based on the Pontryagin Maximum Principle

The talk is motivated by optimal control problems for partial differential equations. The main interest is in problems that involve integral functions of the type \[\int_\Omega g(u(x)) \ dx,\] where $g : \mathbb R \to \mathbb R$ is nonsmooth and nonconvex, and $u$ is the control variable. Examples involve $L^{\scriptscriptstyle r}$-pseudonorms with $r\in [0,1)$ or problems with the constraint $u(x) \in \mathbb Z$ for $x\in \Omega$. Due to the nonconvexity of $g$, the existence of solutions in $L^{\scriptscriptstyle p}$-spaces cannot be proven. Local solutions (if they exist) can be proven to satisfy the Pontryagin maximum principle. A distinctive feature of this result is that no differentiability with respect to the control variable $u$ is required. The maximum principle serves as a starting point to develop an implementable solution algorithm. We prove that the residual in the maximum principle vanishes along the iterates produced by the algorithm. Under additional assumptions, the iterates are a minimizing sequence.

Posted November 2, 2026

Combinatorics Seminar Questions or comments?

2:30 pm – 3:30 pm Zoom

Jessica McDonald, Auburn University
Achieving Steffen’s Edge-Colouring Bound

We discuss the structure of graphs achieving known upper bounds for edge-colouring. In particular we focus on an upper bound of Steffen, and are able to prove that, under some mild assumptions, all critical graphs achieving the bound are so-called odd ring graphs. This is joint work with G. Chen, A. Fiujlaali, and A. Johnson-Yu

Tuesday, November 10, 2026

Posted August 22, 2026

Algebra and Number Theory Seminar Questions or comments?

3:00 pm – 4:00 pm Lockett 233 or click here to attend on Zoom

Isabella Negrini, University of Toronto
TBA

Event contact: Gene Kopp

Posted November 4, 2026
Last modified November 5, 2026

Colloquium Questions or comments?

3:30 pm

Yi Han, Massachusetts Institute of Technology
What Shapes a Random Spectrum?

A large Ginibre matrix fills a disk uniformly with its eigenvalues. A polynomial in several such matrices can produce a very different shape. I will present my work on Brown measure convergence for polynomials in independent complex Ginibre matrices. The proof decomposes a linearization into algebraically irreducible pieces, yielding high-probability lower bounds of the form (N^{-C}) for the least singular value.

I will then present a new approach to inhomogeneous non-Hermitian spectra through direct comparison of logarithmic determinants and transfer-matrix methods, with applications to circular laws at arbitrarily slowly growing bandwidth.

I will also discuss an answer, in unfolded coordinates, to Bourgain’s question about Poisson eigenvalue statistics for one-dimensional Anderson–Bernoulli operators. I will close with uniqueness in law for the scalar stochastic heat equation with uniformly nondegenerate diffusion coefficients of every positive Hölder exponent.

Wednesday, November 11, 2026

Posted August 26, 2026

Informal Analysis Seminar Questions or comments?

12:30 pm – 1:20 pm Lockett 233

Ruben Acevedo Acevedo, Louisiana State University
TBD (Spectral Theory)

Posted September 15, 2026
Last modified November 1, 2026

Geometry and Topology Seminar Seminar website

1:30 pm – 2:30 pm Lockett 233

Federico Galetto, Cleveland State University
Homology of Vietoris-Rips complexes of hypercube graphs

The Vietoris-Rips complex of a point set in a metric space is the simplicial complex of finite subsets of the point set whose elements have mutual distance less than or equal to a given parameter. Our point set is the set of vertices of a hypercube graph equipped with the Hamming distance, and the resulting simplicial complex is symmetric under the action of the automorphism group of the hypercube graph. I will illustrate how this symmetry can be used to compute the homology of some of these Vietoris-Rips complexes. This is joint work with Jonathan Montaño and Zoe Wellner.

Event contact: Christin Bibby

Posted August 27, 2026
Last modified October 13, 2026

Informal Geometry and Topology Seminar Questions or comments?

3:30 pm Lockett Hall 233

Yongho Lee, Louisiana State University
TBD

TBD

Posted November 4, 2026
Last modified November 5, 2026

Colloquium Questions or comments?

3:30 pm

Joe Jackson, University of Chicago
The Mean-Field Limit of Online Stochastic Vector Balancing

This talk will be about recent joint work with Christian Fiedler, Daniel Lacker, and Jonathan Niles-Weed, in which we derive a mean-field scaling limit for a class of combinatorial optimization problems. In particular, we study a stochastic online version of the vector balancing problem: $n$ independent Gaussian random vectors $\mathbf{\zeta}(1),\dots,\mathbf{\zeta}(n) \sim \mathcal{N}(0,I_n)$, each of dimension $n$, arrive one at a time. The goal is to choose signs $\varepsilon(1),\dots,\varepsilon(n) \in \{-1,1\}$, with $\varepsilon(k)$ depending only on $\mathbf{\zeta}(1),\dots,\mathbf{\zeta}(k)$, so as to minimize the expected $\ell^\infty$ norm of the signed sum $\frac{1}{\sqrt{n}}\sum_{k=1}^n \varepsilon(k)\mathbf{\zeta}(k)$. Prior work showed that the optimal value $V^n$ is $O(1)$, at least for vectors with independent Rademacher entries, by constructing and analyzing specific algorithms. Our main contribution is to prove that $V^n$ converges and to characterize its limit $V^\infty$ as the value of a nonstandard stochastic control problem of mean-field type.

Thursday, November 12, 2026

Posted November 2, 2026
Last modified November 5, 2026

Applied Analysis Seminar Questions or comments?

2:00 pm Lockett 232

Zhongkai Tao, IHES
TBA

Posted November 4, 2026
Last modified November 6, 2026

Colloquium Questions or comments?

3:30 pm

Erik Bates, North Carolina State University
Longest convex chains...a new universality class?

In the study of random growth processes, a foundational model is the longest-increasing-subsequence problem: from $n$ independent uniform points in the unit square, find the longest chain whose horizontal and vertical coordinates are both increasing. It is known that the maximal length is asymptotically $2n^{1/2}$, and the longest chain concentrates near the diagonal line $y=x$. In this talk, we add a geometric constraint: the chain must be convex. I will discuss the history of this problem, why I care about it, and what we know so far from recent joint work with Arnab Sen.

Posted October 28, 2026

LSU SIAM Student Chapter

4:00 pm – 6:00 pm TIAMS-4th Floor of Interdisciplinary Science Building

Applied Math Social

Do you use math in your research? Whether you're modeling populations, training neural nets, or running statistics on lab data, join LSU's Society for Industrial and Applied Mathematics (SIAM) on November 12th at 4 PM for an evening of games, food, and networking with people across campus who put math to work. It's a chance to meet potential collaborators and trade research ideas. Grad students, postdocs, faculty, and curious undergrads from all fields are welcome.(This is an interdisciplinary event for many departments.)

Friday, November 13, 2026

Posted September 21, 2026
Last modified November 3, 2026

Control and Optimization Seminar Questions or comments?

10:30 am – 11:20 am Zoom: https://lsu.zoom.us/j/98176468969

Radu Bot, University of Vienna
Continuous- and Discrete-Time Methods in Convex Optimization and Monotone Inclusions

In this talk, we explore the interplay between continuous-time and discrete-time models for solving convex optimization problems and monotone inclusions. We discuss strategies for achieving faster convergence rates across the different settings, as well as issues related to the convergence of trajectories and iterates.

Monday, November 16, 2026

Posted November 4, 2026

Colloquium Questions or comments?

3:30 pm

Thomas Hameister, Boston College
TBA

Tuesday, November 17, 2026

Posted September 20, 2026

Algebra and Number Theory Seminar Questions or comments?

3:00 pm – 4:00 pm Lockett 233 or click here to attend on Zoom

Ngoc Trinh Le, Tulane University
TBA

Event contact: Gene Kopp

Posted November 4, 2026

Colloquium Questions or comments?

3:30 pm

TBA

Posted September 30, 2026
Last modified November 2, 2026

Computational Mathematics Seminar

3:30 pm – 4:20 pm LDMC, Room 1034

Gonzalo Benavides, University of Maryland
A priori error analysis for the Shliomis ferrofluid model without magnetic regularization

We develop and analyze a family of conforming, energy-stable spatial semidiscretizations of the Shliomis ferrofluid model in two and three space dimensions. Unlike many existing numerical analyses, we treat the system without introducing magnetic diffusion. The limited spatial control supplied by the energy law complicates the treatment of magnetic nonlinearities in the error analysis. Our formulation retains the rotational coupling and nonlinear magnetic relaxation and incorporates the magnetic normal-flux condition naturally, overcoming the dimensional restriction and boundary-enforcement difficulties of the two-potential approach of Benavides, Nochetto and Shakipov (2026). The error analysis combines consistent stabilization of the Maxwell constraint with a cancellation arising from exact incompressibility and the pointwise symmetry of the Hessian of the magnetic potential. We prove global solvability of the semidiscrete scheme and establish a priori error estimates for sufficiently regular exact solutions under explicit approximation and projection-stability assumptions. We also construct an averaged $\mathrm{H}^2$-conforming projector, following Girault and Scott (2002), that is defined on $\mathrm{L}^1$, and establish its Sobolev approximation and stability properties. These properties are needed for the error analysis and are of independent interest.

Event contact: Shawn Walker

Wednesday, November 18, 2026

Posted August 26, 2026

Informal Analysis Seminar Questions or comments?

12:30 pm – 1:20 pm Lockett 233

Moisés Gómez-Solís, Louisiana State University
TBD (Spectral Theory)

Event contact: Laura Kurtz

Posted September 15, 2026
Last modified October 31, 2026

Geometry and Topology Seminar Seminar website

1:30 pm – 2:30 pm Lockett 233

Kushlam Srivastava, University of Wisconsin-Milwaukee
Parabolic cut pairs in boundaries of relatively hyperbolic groups

Given a relatively hyperbolic group, the topology of its Bowditch boundary is useful in understanding the underlying relatively hyperbolic structure. For example, for a connected boundary, we know from the work of Hruska–Dasgupta that the cut points are parabolic and correspond to a parabolic splitting of the group. We also know from work of Haulmark–Hruska that inseparable loxodromic cut pairs correspond to splittings over 2–ended subgroups. For some time, it was suspected that inseparable cut pairs on the boundary can only be loxodromic. However, examples of parabolic cut pairs were discovered by Hruska–Walsh. In this talk, we will present a combination theorem for relatively hyperbolic groups, which results in such parabolic cut pairs on their boundaries. We will also see that all relatively hyperbolic groups with parabolic cut pairs are characterized via this theorem.

Event contact: Pallavi Dani

Posted August 27, 2026
Last modified September 25, 2026

Informal Geometry and Topology Seminar Questions or comments?

3:30 pm Lockett Hall 233

Peter Ramsey, Louisiana State University
TBD

TBD

Posted November 4, 2026
Last modified November 5, 2026

Colloquium Questions or comments?

3:30 pm

Xiaonan Liu, Louisiana State University
TBA

Thursday, November 19, 2026

Posted September 10, 2026

Colloquium Questions or comments?

3:30 pm Lockett 232

Maria Chudnovsky, Princeton University MacArthur Foundation Fellowship recipient 2012.
TBA

Friday, November 20, 2026

Posted September 22, 2026
Last modified November 6, 2026

Control and Optimization Seminar Questions or comments?

10:30 am – 11:20 am Zoom: https://lsu.zoom.us/j/98176468969

Rene Henrion, Weierstrass Institute for Applied Analysis and Stochastics, Germany
Chance Constraints in Optimal Control

Chance constraints represent a major tool in stochastic optimization for dealing with random inequality constraints. They allow one to find optimal decisions satisfying the inequality constraints with high probability. Introduced originally in the context of operations research (finite dimensional optimization) with applications among others to water reservoir mangement, capacity expansion in electrical networks or blending problems, they have recently attracted much attention in optimal control, in particular in risk-averse PDE-constrained optimization or in the optimal control of sweeping processes with randomly perturbed control. The talk addresses applications theoretical results (optimality conditions, existence of solutions) as well as algorithmic aspects (spherical-radial decomposition of Gaussian random vectors) related with chance constraints in optimal control.

Posted November 4, 2026

Colloquium Questions or comments?

3:30 pm

Colin Defant, Harvard University
TBA

Monday, November 23, 2026

Posted November 5, 2026

Colloquium Questions or comments?

3:30 pm

Minglei Yang, Oak Ridge National Laboratory
TBA

Monday, November 30, 2026

Posted November 5, 2026

Colloquium Questions or comments?