Pure Lunchtime Seminar talks at Southampton

The talks are all happening at University of Southampton (in person), on Highfield Campus (SO17 1BJ). For the building and the room, see the individual postings. Email the organiser ( a (dot) guidolin (at) soton.ac.uk ) if you have questions.

More Pure Maths talks at Southampton: we run Pure Maths Colloquia, Topology Seminar, and Pure Postgraduate Seminar (link soon).

Upcoming talks

• Mon 16 Feb 2026 12:00 (in 54 / 10031 (10C)): Spencer Goodfellow: Random group actions and stochastic orbit processes
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  This talk connects ideas from geometric group theory, stochastic processes, and machine learning. We present a subtle Lipschitz result showing that for a norm-preserving group action, a bound on the generating set induces a bound on distances between points within an orbit. We begin with graph symmetry as a motivating example: the action of the permutation group on vertices. We then prove our main result in the context of the general theory of stochastic orbit processes. Finally, we explore connections to equivariance in machine learning.

• Mon 2 Mar 2026 12:00 (in 54 / 10031 (10C)): Luke Waite: Title TBA
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  Abstract TBA

• Mon 16 Mar 2026 12:00 (in 54 / 10031 (10C)): Sara Luder: Title TBA
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  Abstract TBA

Recent talks

• Mon 24 Nov 2025 12:00: Indira Chatterji (University of Côte d'Azur): Roughly median geometry
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  I will define roughly median spaces, they include hyperbolic spaces, trees and products of those. I will discuss group actions on roughly median spaces and the conjecture that proper actions on Lp spaces should be equivalent to proper actions on roughly median spaces.

• Mon 10 Nov 2025 12:00: Maximilian Hans: Automorphisms of manifolds
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  The classical Alexander trick implies that the space of homeomorphisms of a d-dimensional disk is contractible. Recent work of Galatius-Randal-Williams and Krannich-Kupers extends this result to contractible manifolds of dimension at least 5. We aim to give a survey of the classical approach to studying automorphisms of manifolds in a modern language, and outline why these techniques currently fail to establish an analogous result in dimension 4. If time permits, we may briefly discuss the approach chosen by the authors named above, and discuss the obstacles to extending it to dimension 4.

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