Junior Geometric Group Theory Seminar
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Mon, 26/04/2010 13:00 |
Nicholas Touikan (UQÀM) |
Junior Geometric Group Theory Seminar  |
SR1 |
| Take a group G and split it as the fundamental group of a graph of groups, then take the vertex groups and split them as fundamental groups of graphs of groups etc. If at some point you end up with a collection of unsplittable groups, then you have a hierarchy. Haken showed that for any 3-manifold M with an incompressible surface S, one can cut M along S and and then find other incompressible surfaces in M and cut again, and repeating this process one eventually obtains a collection of balls. Analogously, Delzant and Potyagailo showed that for any finitely presented group without 2-torsion and a certain sensible class E of subgroups of G, G admits a hierarchy where the edge groups of the splittings lie in E. I really like their proof and I will present it. | |||
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Tue, 04/05/2010 16:00 |
Anne Thomas (Oxford) |
Junior Geometric Group Theory Seminar |
SR1 |
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Tue, 11/05/2010 16:00 |
Andrew Sale (Oxford) |
Junior Geometric Group Theory Seminar |
SR1 |
| I will introduce Symmetric spaces via a result of Kleiner & Leeb, comparing the axioms in their definition of a Euclidean building with properties of symmetric spaces of noncompact type. | |||
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Tue, 18/05/2010 16:00 |
David Hume (Oxford) |
Junior Geometric Group Theory Seminar |
SR1 |
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Tue, 25/05/2010 16:00 |
Oscar Randal-Williams (Oxford) |
Junior Geometric Group Theory Seminar |
SR1 |
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Tue, 01/06/2010 16:00 |
Junior Geometric Group Theory Seminar |
DH 3rd floor SR | |
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Tue, 08/06/2010 16:00 |
Richard Wade (Oxford) |
Junior Geometric Group Theory Seminar |
DH 3rd floor SR |
| Starting from a definition of the cohomology of a group, we will define the bounded cohomology of a group. We will then show how quasi-homomorphisms lead to cocycles in the second bounded cohomology group, and use this to look at the second bounded cohomology of some of our favourite groups. If time permits we will end with some applications. | |||
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Tue, 15/06/2010 16:00 |
Owen Cotton-Barratt (Oxford) |
Junior Geometric Group Theory Seminar |
DH 3rd floor SR |
