Thu, 06 Feb 2025
17:00
L3

Asymptotic theories: from finite structures to infinite fields

Philip Dittmann
(University of Manchester)
Abstract

I will discuss several interesting examples of classes of structures for which there is a sensible first-order theory of "almost all" structures in the class, for certain notions of "almost all". These examples include the classical theory of almost all finite graphs due to Glebskij-Kogan-Liogon'kij-Talanov and Fagin (and many more examples from finite model theory), as well as more recent examples from the model theory of infinite fields: the theory of almost all algebraic extensions and the universal/existential theory of almost all completions of a global field (both joint work with Arno Fehm). Interestingly, such asymptotic theories are sometimes quite well-behaved even when the base theories are not.

Mon, 17 Feb 2025
16:00
C6

TBC

Jori Merikowski
(University of Oxford)
Abstract

TBC

Mon, 03 Feb 2025
16:00
C6

Progress towards the Keating-Snaith conjecture for quadratic twists of elliptic curves

Nathan Creighton
(University of Oxford)
Abstract

The Keating-Snaith conjecture for quadratic twists of elliptic curves predicts the central values should have a log-normal distribution. I present recent progress towards establishing this in the range of large deviations of order of the variance. This extends Selberg’s Central Limit Theorem from ranges of order of the standard deviation to ranges of order of the variance in a variety of contexts, inspired by random walk theory. It is inspired by recent work on large deviations of the zeta function and central values of L-functions.
 

Free field realisation of boundary vertex algebras for Abelian gauge theories in three dimensions
Beem, C Communications in Mathematical Physics volume 406 issue 5 (29 Apr 2025)
A continuum model for the elongation and orientation of Von Willebrand Factor with applications in arterial flow
Yeo, E Oliver, J Korin, N Waters, S (24 Nov 2023)
Sparse identification of nonlocal interaction kernels in nonlinear gradient flow equations via partial inversion
Carrillo de la Plata, J Estrada-Rodriguez, G Mikolás, L Tang, S Mathematical Models and Methods in Applied Sciences volume 35 issue 05 1073-1131 (07 Feb 2025)
Fri, 24 Jan 2025
15:00
L4

Efficient computation of the persistent homology of Rips complexes

Katharine Turner
(Australian National University)

Note: we would recommend to join the meeting using the Teams client for best user experience.

Abstract

Given a point cloud in Euclidean space and a fixed length scale, we can create simplicial complexes (called Rips complexes) to represent that point cloud using the pairwise distances between the points. By tracking how the homology classes evolve as we increase that length scale, we summarise the topology and the geometry of the “shape” of the point cloud in what is called the persistent homology of its Rips filtration. A major obstacle to more widespread take up of persistent homology as a data analysis tool is the long computation time and, more importantly, the large memory requirements needed to store the filtrations of Rips complexes and compute its persistent homology. We bypass these issues by finding a “Reduced Rips Filtration” which has the same degree-1 persistent homology but with dramatically fewer simplices.

The talk is based off joint work is with Musashi Koyama, Facundo Memoli and Vanessa Robins.

Subscribe to