Tag Archives: Cambridge NPC seminar

Notes of Karen Vogtmann’s second Cambridge lecture 23-06-2017

The borders of Outer Space Joint work with Kai-Uwe Bux and Peter Smillie. 1. Duality groups I am interested in Poincare duality. For a group, assume is a smooth -manifold, then Bieri-Eckmann observed that is suffices that acts freely cocompactly … Continue reading

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Notes of Grigori Avramidi’s Cambridge lecture 23-06-2017

Topology of ends of nonpositively curved manifolds Joint work with T. Nguyen Pham. I am interested in complete Riemannian manifolds with curvature in , and finite volume. Example. Product of two hyperbolic surfaces. The end is homeomorphic to , with … Continue reading

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Notes of Christopher Leininger’s Cambridge lecture 23-06-2017

Free-by-cyclic groups and trees Joint work with S. Dowdall and I. Kapovich. The Bieri-Neumann-Strebel invariant is an open subset of , it is the set of such that is surjective on . Here, is the torsion free abelian cover of … Continue reading

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Notes of Kevin Shreve’s Cambridge lecture 23-06-2017

Action dimension and Cohomology Joint work with Giang Le and Mike Davis. 1. Action dimension This is the minimal dimension of contractible manifolds which admit a proper -action. The geometric dimension replaces manifolds with complexes. 1.1. Examples If is of … Continue reading

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Notes of Bill Goldman’s Cambridge lecture 23-06-2017

The dynamics of classifying geometric structures 1. Marked geometric structures Moduli spaces of geometric structures do not all behave like the moduli space of Riemann surfaces: in general, it is not a well behaved space, it is a quotient by … Continue reading

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Notes of Denis Osin’s Cambridge lecture 22-06-2017

Extending group actions on metric spaces Joint work with David Hume and C. Abbott. Question. Let be groups. Given an isometric action of on a metric space , does it extend to an action on a (possibly different) metric space … Continue reading

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Notes of Jean-Fran├žois Lafont’s Cambridge lecture 22-06-2017

Hyperbolic groups whose boundary is a Sierpinski -space Joint work with Bena Tshishiku. 1. Sierpinski -space Start with an -dimensional sphere. Remove a dense family of balls with disjoint interiors. Get . Up to homeo, balls need not be round. … Continue reading

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