Also take a look at our interactive calendar:
Events of week
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Special Event October 3-5
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American Mathematical Society
The 2025 Fall Southeastern Sectional Meeting
Host: Victory Moll
I hope you can participate.
Here is the link
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Week of October 17 - October 13
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October 15
Probability & Statistics
Topic: Scalable topic modelling decodes spatial tissue architecture for large-scale multiplexed imaging analysis
Speaker: Xiyu Peng - Texas A&M University
Abstract: Recent progress in multiplexed tissue imaging is advancing the study of tumor microenvironments to enhance our understanding of treatment response and disease progression. Despite its popularity, there are significant challenges in data analysis, including high computational demands that limit feasibility for large-scale applications and the lack of a principled strategy for integrative analysis across images. To overcome these challenges, we introduce a spatial topic model designed to decode high-level spatial architecture across multiplexed tissue images. Our method integrates both cell type and spatial information within a topic modelling framework, originally developed for natural language processing and adapted for computer vision. We benchmarked its performance through various case studies using different single-cell spatial transcriptomic and proteomic imaging platforms across different tissue types. We show that our method runs significant faster on large-scale image datasets, along with high precision and interpretability. It consistently identifies biologically and clinically significant spatial “topics”, such as tertiary lymphoid structures.
Location: Dinwiddie Hall 108 (DW 108)
Time: 3:00 PM
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Week of September 27 - October 3
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October 01
Algebra and Combinatorics
Topic: The weight-0 compactly supported Euler characteristic of moduli spaces of marked hyperelliptic curves
Speaker: Madeline Brandt - Vanderbilt University
Abstract: Deligne connects the weight-zero compactly supported cohomology of a complex variety to the combinatorics of its compactifications. In this talk, we use this to study the moduli space of n-marked hyperelliptic curves. We use moduli spaces of G-admissible covers and tropical geometry to give a sum-over-graphs formula for its weight-0 compactly supported Euler characteristic, as a virtual representation of S_n. This is joint work with Melody Chan and Siddarth Kannan.
Location: Richardson Building, 108
Time: 3:00
October 01
Probability & Statistics
Topic: Causal Inference in Pharmaceutical Statistics
Speaker: Yixin Fang - AbbVie
Abstract: In this talk, the estimand framework followed in the pharmaceutical industry will be discussed, using the language of causal inference. The definition of causal estimand and statistical estimand will be addressed, as well as the differences between randomized controlled trials (RCT) and non-interventional studies (NIS). Two basic identification strategies—the G-formula strategy and the weighting strategie—will be presented. With regard to estimation of the estimand, doubly robust methods will be discussed.
Additionally, a brief description will be provided of the difference between FDA submissions, which are focused on regulatory approval for marketing a product, and HTA submissions, which are focused on gaining reimbursement and demonstrating value to payers and healthcare systems. In particular, methods for direct and indirect comparisons will be discussed.
In summary, this talk is intended to serve as a high-level introduction to important causal inference topics for students interested in pursuing a career in the pharmaceutical industry.
Please join this seminar via: https://tulane.zoom.us/j/97158638464
Location: Zoom only 971 5863 8464
Time: 3:00 PM
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Week of September 26 - September 27
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September 25,
Colloquium
Topic: Riding the neural waves: Mathematics of nonlocally coupled waves in active media
Bard Ermentrout - University of Pittsburgh Host: (Lisa Fauci)
Abstract: Recent improvements in technology have enabled neuroscientists to simultaneously record activity of many neurons at high spatial and temporal resolution. This has allowed them to discover that activity is organized into a variety of spatial patterns such as plane waves, bullseyes, and rotating waves. In this talk, I want to distinguish two different classes or wave-like activity: (1) evoked waves or "trigger waves", and (2) phase waves. In the former, the onset of activity in one area requires prior activity in a neighboring area, while in the latter, the apparent wave motion is a consequence of timing differences between areas. I will present some recent results on the role of inhibition in controlling the propagation and stability of trigger waves. Next, I will consider coupled phase equations that describe spatio-temporal activity in intrinsically oscillatory media. I will describe recent work where we are able to extract hidden waves from human cortical recordings. Finally, I will present some work showing how ongoing phase waves can promote the propagation of trigger waves in an anisotropic manner.
Location: Gibson Hall 126-A
Time: 3:30 pm
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September 24
Algebra and Combinatorics
Topic: Generalized Hilbert Kunz Multiplicities of Families of Ideals
Speaker: Stephen Landsittel - Harvard University and Hebrew University of Jerusalem
Abstract: We discuss existence and volume equals multiplicity for generalized Hilbert Kunz Multiplicities for p-families of ideals. We also exhibit Minkowski inequalities for p-families.
Location: Richardson Building 108
Time: 3:00
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September 23,
Graduate Student Colloquium
Topic: Generating Functions and Modular Forms
Speaker: Peter Marcus - Tulane University
Abstract: A generating function is a series whose coefficients are a sequence of interest. They are one of the most important tools in analytic number theory. I will give an introduction to generating functions and talk about an example from my research, the generating function for k-regular partition numbers.
Location: Dinwidie Hall 102
Time: 3:30
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Week of September 19 - September 15
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September 17
Algebra and Combinatorics
Topic: Interpolation in weighted projective space
Speaker: Shah Roshan Zamir - Tulane University
Abstract: Over an algebraically closed field, the double point interpolation problem asks for the vector space dimension of the projective hypersurfaces of degree d singular at a given set of points. After being open for 90 years, a series of papers by J. Alexander and A. Hirschowitz in 1992--1995 settled this question in what is referred to as the Alexander-Hirschowitz theorem. In this talk, we primarily use commutative algebra to prove analogous statements in the weighted projective space, a natural generalization of the projective space. We will also introduce an inductive procedure, originally due to A. Terracini from 1915, to demonstrate the only example of a weighted projective plane, of a particular family, where the analogue of the Alexander-Hirschowitz theorem holds without any exceptions. Furthermore, we will give interpolation bounds for an infinite family of weighted projective planes. There are no prerequisites for this talk besides some elementary knowledge of commutative algebra.
Location: Richardson Building 108
Time: 3:00
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September 16,
Graduate Student Colloquium
Topic: Markov Chains and their Applications to Game State Modeling
Speaker: Rebecca Kahler - Tulane University
Abstract: Markov Chains are (stochastic) processes where the probability of the next state depends solely on the current state (the past states don’t tell you anything about the next state). My talk will introduce Markov Chains, cover a few simple examples, and then we will use the processes to model simple games like Rock, Paper, Scissors.
Location: Dinwidie Hall 102
Time: 3:30
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Week of September 12 - September 8
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September 9,
Graduate Student Colloquium
Topic: Tevelev Degrees for genus-zero curves in blowup of P^3 at a point.
Speaker: Naufil Sakran - Tulane University
Abstract: In this talk, I would like to answer the following question:
Let $X$ denote the space of blow-up of $\mathbb{P}^3$ at a point. If we fix $n$-points, then how many genus 0 curves can be drawn on $X$ passing through the $n$-points?
The study of such questions lies in the field of enumerative geometry, and I would like to give a glimpse of this subject by answering the above question completely.
Location: Richardson Building, 102
Time: 3:30
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September 9
Algebra and Combinatorics
Topic: Oriented matroids from non-polyhedral cones
Speaker: Catherine Babecki - California Institute of Technology Host: (Dan Bernstein)
Abstract: Existing generalizations of matroids to infinite settings are combinatorial in nature-- we propose a geometric alternative. One perspective on realizable oriented matroids comes from vector configurations and linear dependences among them. Pulling this back a step, the circuits (minimal dependences) are exactly the support-minimal vectors which lie in the null space of a linear map. We define conic matroids in a way that mimics this, and in particular, the "face-minimal" vectors in a subspace form a conic matroid analogously to standard realizable matroids. If the cone is the nonnegative orthant, we recover standard realizable oriented matroids. We will discuss our precise definitions, show how this structure captures features of Gale duality and conic programming, and share some of the directions we have yet to make headway in. Joint work with Isabelle Shankar and Amy Wiebe.
Location: Richardson Building 108
Time: 3:00
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September 8
Integrability and Beyond
Topic: Power Spectrum Analysis for the Circular Unitary Ensemble
Speaker: Roman Riser - Tulane University
Abstract: The power spectrum has emerged as an effective tool for studying both system-specific and universal properties of quantum systems. In these 3 lectures we will study the power spectrum for the circular unitary ensemble (CUE). In the introduction, I will give an overview of results for the power spectrum. This will include a plot of the asymptotic limit for the CUE. We will compare it with numerical results for the zeros of the Riemann zeta function.
In the first lecture, I will derive a general representation for the power spectrum. Then we will review the definition and basic properties of the CUE and its joint probability distribution function of the eigenvalues. Next we deduce an exact representation of the power spectrum for the CUE with $N$ eigenvalues. In the second lecture, we will discuss the limit $N\rightarrow\infty$ and find a parameter free representation given in terms of the Painlev\'e V transcendent. In the last lecture, we will analyze the asymptotic formula and discuss its numerical evaluation.
Location: TBA
Time: 3:00
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Week of September 5 - 1
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September 3
Algebra and Combinatorics
Topic: A summation formula for mock modular forms
Speaker: Kalani Thalagoda - Tulane University
Abstract: Analytic number theorists frequently use summation formulas to study the asymptotic and statistical behavior of interesting (and sometimes erratic) arithmetic functions. For Dirichlet series satisfying a certain functional equation, Chandrasekharan and Narasimhan proved a formula for a weighted sum of the first n coefficients. In this talk, I will discuss a summation formula for mock modular forms of moderate growth and an application of it to Hurwitz class numbers. This is joint work with Olivia Beckwith, Nicholas Diamantis, Rajat Gupta, and Larry Rolen.
Location: Richardson Building 108
Time: 3:00
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September 3,
Graduate Student Colloquium
Topic: A summation formula for mock modular forms
Speaker: Kalani Thalagoda - Tulane University
Abstract: Analytic number theorists frequently use summation formulas to study the asymptotic and statistical behavior of interesting (and sometimes erratic) arithmetic functions. For Dirichlet series satisfying a certain functional equation, Chandrasekharan and Narasimhan proved a formula for a weighted sum of the first n coefficients. In this talk, I will discuss a summation formula for mock modular forms of moderate growth and an application of it to Hurwitz class numbers. This is joint work with Olivia Beckwith, Nicholas Diamantis, Rajat Gupta, and Larry Rolen.
Location: Richardson Building, 108
Time: 3:00
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02, September
Graduate Student Colloquium
Topic: Rosenbrock Time Integration for Proper Orthogonal Decomposition(POD) based Reduced-Order Modeling (POD-ROM) of Dynamical System
Speaker: Moslem Uddin - Tulane University
Abstract: Proper Orthogonal Decomposition (POD) provides an efficient method for obtaining low-dimensional, physically meaningful models from high-dimensional dynamical systems. In this talk, we use the Brusselator reaction-diffusion system as a guide to demonstrate the mathematics behind and application of POD-based reduced-order modeling (POD-ROM). We discuss how to construct the POD basis from simulation data, highlight its optimality and interpretability, and show how it enables significant dimensionality reduction without sacrificing essential dynamics. Stable simulation of reduced-order systems is ensured by the incorporation of Rosenbrock-Wanner (ROW) time-stepping techniques. We discuss computational complexity, elucidating the distinction between offline (basis construction) and online (ROM evolution) costs, and show how mode selection affects physical fidelity, speed, and accuracy. The talk concludes with views on current directions, potential difficulties, and best practices in data-driven model reduction for complex systems.
Location: Dinwiddie Hall DW-102
Time: 3:30
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