Fri, 21 Feb 2025

13:00 - 14:00
Quillen Room

Hilbert’s Fourteenth problem and the finite generation ideal of Daigle and Freudenberg’s counterexample

Simon Hart
(University of York)
Abstract

Hilbert’s fourteenth problem is concerned with whether invariant rings under algebraic group actions are finitely generated. A number of examples have been constructed since the mid-20th century which demonstrate that this is not always the case. However such examples by their nature are difficult to construct, and we know little about their underlying structure. This talk aims to provide an introduction to the topic of Hilbert’s fourteenth problem, as well as the finite generation ideal - a key tool used to further understand these counterexamples. We focus particularly on the example constructed by Daigle and Freudenberg at the turn of the 21st century, and describe the work undertaken to compute the finite generation ideal of this example. 

Mon, 20 Jan 2025
14:15
L5

Yang-Mills on an ALF-fibration

Jakob Stein
(UNICAMP)
Abstract

In this talk, we will make an explicit link between self-dual Yang-Mills instantons on the Taub-NUT space, and G2-instantons on the BGGG space, by displaying the latter space as a fibration by the former. In doing so, we will discuss analysis on non-compact manifolds, circle symmetries, and a new method of constructing solutions to quadratically singular ODE systems. This talk is based on joint work with Matt Turner: https://arxiv.org/pdf/2409.03886

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applications
Janzer, B Janzer, O Methuku, A Tardos, G (11 Nov 2024) http://arxiv.org/abs/2411.07188v1
On the first-order free group factor alternative
Goldbring, I Pi, J Journal of Operator Theory
Fluid relaxation approximation of the Busenberg--Travis cross-diffusion
system
Carrillo, J Chen, X Du, B Jüngel, A Communications in Mathematical Physics (10 Nov 2024) http://arxiv.org/abs/2411.06460v1
Random walk models in the life sciences: including births, deaths and
local interactions
Plank, M Simpson, M Baker, R (17 Nov 2024) http://arxiv.org/abs/2411.10972v1
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