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 2 Nov 2026 12:00 (in 54 / 10037 (10B)): William D Cohen (Cambridge): Artin Groups and the Tits Alternative
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  In 1995 Bestvina asked which Artin groups satisfy the Tits alternative, a classical condition for group which governs the behaviour of subgroups, and since then much progress has been made in classifying particular subclasses of Artin groups with respect to this property. In this talk I will briefly outline the history of this important problem in the world of Artin groups, and present a combination theorem for the Tits alternative for Artin groups that allows us to find a wealth of new examples of Artin groups satisfying the Tits alternative that do not come from the previously known classes.

• Mon 9 Nov 2026 12:00 (in 54 / 10037 (10B)): Kim Ruane (Tufts): Abstract TBA
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  Abstract TBA

• Mon 23 Nov 2026 12:00 (in 54 / 10037 (10B)): James Binnie (Cardiff): Title TBA
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  Abstract TBA

Recent talks

• Mon 12 Oct 2026 12:00: Armando Martino: Branch groups, automorphisms and overlap maps
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  Branch groups offer fascinating examples in group theory, generalising the deep work of Grigorchuk who produced a group of intermediate growth, which is also amenable but not elementarily amenable.

  I would like to discuss a recent result which asks the following question: Given a branch group, or weakly branch group, can the automorphisms of that group be realised as automorphisms of the locally finite rooted tree?

  We show that the answer is positive, if one is allowed to change the tree while still retaining the (weakly) branch property.

  The idea is to use the structure and topology of the boundary via overlap maps, which are simply the Gromov product on the boundary of the tree.

• Mon 28 Sep 2026 12:00: Gareth Jones: The Macbeath-Hurwitz groups, maps and surfaces
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  The Macbeath-Hurwitz groups, of type PSL(2,q), are the orientation-preserving automorphism groups of certain highly symmetric maps and Riemann surfaces. Around 50 years ago Wendy Hall, in her Southampton PhD thesis, studied the full automorphism groups of these maps and surfaces, and their possible non-orientable quotients, with some early computational evidence for small q. I have used density theorems from number theory to obtain asymptotic versions of her results, and have extended them to similar surfaces and maps of other types.

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