Title: The topology of G2-structures on 7-manifolds
Speaker: Diarmuid Crowley, Bonn
Date: Tuesday, August 26, 2014
Time: 11:00am-12:00pm
Place: Seminar Room 313, Simons Center
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Abstract: In this talk I discuss the problem of counting the number of G2-structures on a spin 7-manifold M up to deformation: i.e. homotopies and the action of diffeomorphisms.
For general M, there is an invariant, the \nu-invariant, which distinguishes at least 24 deformation classes of G2-structure on every spin 7-manifold. When M is 2-connected it is possible to count the number of deformation classes exactly.
The material in this talks is based on recent joint work with Johannes Nordström.