# Past Kinderseminar

23 January 2013
10:30
Martin Palmer -- Queen's Lecture C
Abstract

There appears to be no universally accepted rigorous definition of a "flexagon" (although I will try to give a reasonable one in the talk). Examples of flexagons were most likely discovered and rediscovered many times in the past - but they were "officially" discovered in 1939, a serendipitous consequence of the discrepancy between US paper sizes and sensible paper sizes.* I'll describe a couple of the most famous examples of flexagons (with actual models to play with of course), and also introduce some of the more abstract theory of flexagons which has been developed. Feel free to bring your own models of flexagons!

* The views expressed herein are solely those of the speaker, and do not reflect the official position of the Kinderseminar w.r.t. international paper standards.

• Kinderseminar
16 January 2013
10:30
Alejandra Garrido -- Queen's Lecture C
Abstract
• Kinderseminar
24 October 2012
11:00
John Mackay -- St Hugh's, 80WR18
Abstract
• Kinderseminar
17 October 2012
11:00
Alejandra Garrido Angulo -- St Hugh's, 80WR18
Abstract

I will give a brief report on some the topics discussed at the workshop "Golod-Shafarevich groups and rank gradient" that took place this August in Vienna. I will focus on results involving rank gradient.

• Kinderseminar
23 May 2012
11:30
Dawid Kielak
Abstract
• Kinderseminar
16 May 2012
11:30
Martin Bridson
Abstract
• Kinderseminar
7 March 2012
11:30
Elisabeth Fink
Abstract
• Kinderseminar
22 February 2012
11:30
$\Pi$eter Neumann
Abstract
• Kinderseminar
15 February 2012
(All day)
Jason Semeraro
Abstract
Saturated fusion systems are a relatively new class of objects that are often described as the correct 'axiomatisation' of certain p-local phenomena in algebraic topology. Despite these geometric beginnings however, their structure is sufficiently rigid to afford its own local theory which in some sense mimics the local theory of finite groups. In this talk, I will briefly motivate the definition of a saturated fusion system and discuss a remarkable result of Michael Aschbacher which proves that centralisers of normal subsystems of a saturated fusion system, F, exist and are themselves saturated. I will then attempt to justify his definition in the case where F is non-exotic by appealing to some classical group theoretic results. If time permits I will speculate about a topological characterisation of the centraliser as the set of homotopy fixed points of a certain action on the classifying space of F.
• Kinderseminar
8 February 2012
11:30
Tom Sutherland
Abstract
• Kinderseminar