Tue, 17 Jun 2025
14:00
C6

Lagrangian mean curvature flow out of conical singularities

Spandan Ghosh
(University of Oxford)
Abstract

Lagrangian mean curvature flow (LMCF) is a way to deform Lagrangian submanifolds inside a Calabi-Yau manifold according to the negative gradient of the area functional. There are influential conjectures about LMCF due to Thomas-Yau and Joyce, describing the long-time behaviour of the flow, singularity formation, and how one may flow past singularities. In this talk, we will show how to flow past a conically singular Lagrangian by gluing in expanders asymptotic to the cone, generalizing an earlier result by Begley-Moore. We solve the problem by a direct P.D.E.-based approach, along the lines of recent work by Lira-Mazzeo-Pluda-Saez on the network flow. The main technical ingredient we use is the notion of manifolds with corners and a-corners, as introduced by Joyce following earlier work of Melrose.

Tue, 17 Jun 2025
16:00
L6

Quantum Chaos, Random Matrices, and Spread Complexity of Time Evolution.

Vijay Balasubramanian
(University of Pennsylvania)
Abstract

I will describe a measure of quantum state complexity defined by minimizing the spread of the wavefunction over all choices of basis. We can efficiently compute this measure, which displays universal behavior for diverse chaotic systems including spin chains, the SYK model, and quantum billiards.  In the minimizing basis, the Hamiltonian is tridiagonal, thus representing the dynamics as if they unfold on a one-dimensional chain. The recurrent and hopping matrix elements of this chain comprise the Lanczos coefficients, which I will relate through an integral formula to the density of states. For Random Matrix Theories (RMTs), which are believed to describe the energy level statistics of chaotic systems, I will also derive an integral formula for the covariances of the Lanczos coefficients. These results lead to a conjecture: quantum chaotic systems have Lanczos coefficients whose local means and covariances are described by RMTs. 
 

Fri, 20 Jun 2025
13:00
L5

Latent Space Topology Evolution in Multilayer Perceptrons

Eduardo Paluzo Hidalgo
(University of Seville)
Abstract

In this talk, we present a topological framework for interpreting the latent representations of Multilayer Perceptrons (MLPs) [1] using tools from Topological Data Analysis. Our approach constructs a simplicial tower, a sequence of simplicial complexes linked by simplicial maps, to capture how the topology of data evolves across network layers. This construction is based on the pullback of a cover tower on the output layer and is inspired by the Multiscale Mapper algorithm. The resulting commutative diagram enables a dual analysis: layer persistence, which tracks topological features within individual layers, and MLP persistence, which monitors how these features transform across layers. Through experiments on both synthetic and real-world medical datasets, we demonstrate how this method reveals critical topological transitions, identifies redundant layers, and provides interpretable insights into the internal organization of neural networks.

 

[1] Paluzo-Hidalgo, E. (2025). Latent Space Topology Evolution in Multilayer Perceptrons arXiv:2506.01569 
Fri, 13 Jun 2025
13:00
L5

The Likelihood Correspondence

Hal Schenck
(Auburn University)
Abstract

An arrangement of hypersurfaces in projective space is strict normal crossing if and only if its Euler discriminant is nonzero. We study the critical loci of all Laurent monomials in the equations of the smooth hypersurfaces. These loci form an irreducible variety in the product of two projective spaces, known in algebraic statistics as the likelihood correspondence and in particle physics as the scattering correspondence. We establish an explicit determinantal representation for the bihomogeneous prime ideal of this variety.

Joint work with T. Kahle, B. Sturmfels, M. Wiesmann

Further mechanistic insights into the trophic design of free-living mites
Bowman, C Acarologia
Thu, 12 Jun 2025
17:00
L3

Hrushovski constructions in ordered fields

Yilong Zhang
(Universitat Bonn)
Abstract
Hrushovski constructions are a variant of amalgamation methods. They were invented to construct new examples of strongly minimal theories. The method was later adapted to expansions of fields, including colored fields and powered fields. In this talk, I will present my attempt to apply Hrushovski constructions to ordered fields. I will construct an expansion of RCF by a dense multiplicative subgroup (green points). Hrushovski constructions induce a back-and-forth system, enabling us to study the dp-rank and the open core of this structure. I will also introduce my recent progress on powered fields, an expansion of RCF by "power functions" on the unit circle, and my plan to axiomatize expansions of the real field using Hrushovski constructions.
Reducing phenotype-structured partial differential equations models of cancer evolution to systems of ordinary differential equations: a generalised moment dynamics approach
MAINI, P Villa, C Browning, A Jenner, A Journal of Mathematical Biology

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