Also take a look at our interactive calendar:
Events of week
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Spring 2026 Math For All; April 10-11, 2026
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Week of January 30 - January 26
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January 29, 2026
*** Special Colloquium ***
Topic: Tractability of chaotic dynamics in noisy systems
Speaker: Alex Blumenthal - Georgia Tech
Abstract: Many real-world systems exhibit dynamical chaos, characterized by sensitive dependence on initial conditions and intricate, seemingly disordered behavior. While existing abstract tools from smooth ergodic theory provide a rich framework for understanding chaotic dynamics, verifying this framework in concrete systems remains a notoriously difficult problem. Even in low-dimensional toy models, rigorous proofs often lag significantly behind compelling numerical evidence. Remarkably, this problem becomes far more tractable when systems are subjected to external, time-dependent stochastic forcing. In such settings, the scope of systems for which chaotic hallmarks can be rigorously established expands dramatically, offering substantive progress toward the original promise of chaos theory: to explain and quantify dynamical disorder in nature. I will present several applications of these ideas, including towards disordered dynamical behavior exhibited in systems from fluid mechanics. This talk will include joint work with many collaborators, including Lai-Sang Young, Jinxin Xue, Jacob Bedrossian, and Sam Punshon-Smith.
Location: TBA
Time: 3:30 PM
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January 28, 2026
Algebra and Combinatorics
Topic: Chow rings of moduli spaces of genus 0 curves with collisions
Speaker: William Newman - Ohio State University
Abstract: Simplicially stable spaces are alternative compactifications of M_{g,n} generalizing Hassett’s moduli spaces of weighted stable curves. We give presentations of the Chow rings of these spaces in genus 0. When considering the special case of \bar M_{0,n}, this gives a new proof of Keel’s presentation of CH(\bar M_{0,n}).
Location: Gibson Hall 126
Time: 3:00 PM
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January 27, 2026
Graduate Student Colloquium
Topic: Microscale flows around a sphere under random forcing or minimal microorganism models
Speaker: Erene Erazo - Tulane University
Abstract: In this talk, I will discuss microscale flows around a sphere under random forcing or minimal microorganism models. First, I will introduce a model that describes the dynamical behavior of small spherical particles immersed in a viscous fluid under the influence of thermal fluctuations. We perform theoretical and numerical analyses of particle diffusion to characterize their motion across varying particle sizes. Second, using the same framework, I will present a minimal model for swimmers and discuss some preliminary results.
Location: Dinwiddie Hall 102
Time: 2:15 PM
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Week of January 23 - January 19
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January 22, 2026
*** Special Colloquium ***
Topic: Large Effects in Perturbed Hamiltonian Systems
Speaker: Marian Gidea - Yeshiva University
Abstract: One of the fundamental laws of physics is the conservation of energy, which states that the total energy of an isolated system remains constant.
Hamiltonian dynamics provides a natural framework for modeling this law. However, real-life systems are rarely isolated and are subject to external perturbations of various types, such as periodic / quasi-periodic forcing, random perturbations, or dissipation. In this lecture, we will consider several models from celestial mechanics, engineering, and biology, and study the effects of perturbations on these systems. The upshot is that even small perturbations can accumulate over time, giving rise to large effects, such as significant energy growth, and trajectories that wander far from their initial point. In particular, we will address conjectures proposed by Arnold (1964) and Chirikov (1979).
Location: Dinwiddie 108
Time: 3:30 PM
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January 21, 2026
Algebra and Combinatorics
Topic: When Schubert Varieties Miss Being Toric by One
Speaker: Mahir Bilen Can - Tulane University
Abstract: Schubert and Richardson varieties in flag varieties provide a rich testing ground for various group actions. In this talk I will discuss two “borderline toric” phenomena. First, I will introduce nearly toric Schubert varieties. They are spherical Schubert varieties for which the smallest codimension of a torus orbit is one. Then I will explain a simple Coxeter-type classification of these examples, and why this “one step from toric” condition forces strong spherical behavior (in particular, it produces a large family of doubly-spherical Schubert varieties). Time permitting, I will also discuss toric Richardson varieties and a type-free combinatorial criterion: a Richardson variety is toric exactly when its Bruhat interval is a lattice (equivalently, it contains no subinterval of type S3, under a mild dimension hypothesis).
Location: Gibson Hall 126
Time: 3:00 PM
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January 20, 2026
*** Special Colloquium ***
Topic: Evolution equations in physical and biological systems
Speaker: Selim Sukhtaiev - Auburn University
Abstract: Disorder and pattern formation are central themes in modern science, and both play a fundamental role in the behavior of complex physical and biological systems. In this talk, we will discuss two mathematical models that illustrate these phenomena: the Anderson model of electronic transport in random media and the Keller–Segel model of chemotaxis.
We will first turn to a mathematical treatment of the Anderson model. We will discuss several natural Hamiltonians on metric trees with random branching numbers and show that their transport properties are suppressed by disorder. This phenomenon, known as Anderson localization, is a hallmark of the spectral theory of Schrodinger operators.
We will then consider the Keller–Segel system, a coupled pair of reaction–advection–diffusion equations describing the collective motion of cells in response to chemical signals. We will focus on well-posedness of this system on arbitrary compact networks, as well as the asymptotic stability, instability, and bifurcation of steady states in both the parabolic–parabolic and parabolic–elliptic realizations of the Keller–Segel model.
Location: Dinwiddie 108
Time: 3:30 PM
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Week of January 16 - January 12
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January 16, 2026
Applied and Computational Math
Topic: Soliton Gas: recent results in one and two dimensions
Speaker: Giacomo Roberti - Northumbria University Newcastle, UK (Host): Kenneth McLaughlin
Abstract: The concept of integrable turbulence, introduced by Zakharov in 2009, provides a framework for describing random nonlinear dispersive waves governed by integrable equations, such as the Korteweg–de Vries (KdV) and the focusing nonlinear Schrödinger (fNLS) equations.
Within this framework, we focus on a specialized class of integrable turbulence dominated by solitons, known as a soliton gas, first introduced by Zakharov in 1971.
In recent years, there has been rapidly growing interest in soliton gas theory and its applications, as soliton gas dynamics have been shown to underpin a wide range of fundamental nonlinear wave phenomena, including modulational instability and the formation of rogue waves.
In this talk, we present recent results on one-dimensional soliton gases, with particular emphasis on the collision of monochromatic soliton gases, as well as recent extensions of the theory to two-dimensional soliton gases.
Location: Gibson Hall, room 126
Time: 3:00 PM
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January 14, 2026
Algebra and Combinatorics
Topic: Frobenius singularities of permanental varieties
Speaker: Trung Chau - Chennai Mathematical Institute (Host): Tai Ha
Abstract: A permanent of a square matrix is exactly its determinant with all minus signs becoming plus. Despite the similarities, the computation of a determinant can be done in polynomial time, while that of a permanent is an NP-hard problem. In 2002, Laubenbacher and Swanson defined P_t(X) to be the ideal generated by all t-by-t subpermanents of X, and called it a permanental ideal. This is a counterpart of determinantal ideals, the center of many areas in Algebra and Geometry. We will discuss properties of P_2(X), including their Frobenius singularities over a field of prime characteristic, and related open questions.
Location: Gibson Hall, room 126
Time: 3:00 PM
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January 12, 2026
Soliton gas description of modulational instability
Topic: Soliton gas description of modulational instability
Speaker: Thibault Congy - Northumbria University, Newcastle, U.K.
Abstract: Soliton gases are infinite random ensembles of interacting solitons whose large-scale dynamics are governed by the elementary two-soliton collisions. By applying the spectral theory of soliton gases to the focusing nonlinear Schrödinger equation (fNLSE), we can describe the statistically stationary and spatially homogeneous integrable turbulence that emerges at large times from the spontaneous (noise-induced) modulational instability of the plane-wave and the elliptic “dn” solutions.
I will show that a special, critically dense soliton gas—the bound-state soliton condensate—provides an accurate model for the asymptotic state of both plane-wave and elliptic integrable turbulence. Moreover, certain statistical moments of the resulting turbulence can be computed analytically, allowing us to assess deviations from Gaussianity. These analytical predictions demonstrate excellent agreement with direct numerical simulations of the fNLSE.
The talk is based on the recent works:
“Statistics of Extreme Events in Integrable Turbulence”, T. Congy, G. A. El, G. Roberti, A. Tovbis, S. Randoux, and P. Suret, Phys. Rev. Lett. 132, 207201 (2024).
“Spontaneous modulational instability of elliptic periodic waves: The soliton condensate model”, D. S. Agafontsev, T. Congy, G. A. El, S. Randoux, G. Roberti, and P. Suret, Physica D 134956 (2025).
Location: Gibson Hall 126A
Time: 3:00 PM
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