Geometric Topology Seminars: Bruno Martelli and Daniele Zuddas (14/12/2022)
Wednesday 14th December 2022 - on line: https://meet.google.com/xqc-udeq-vwf
at 3 p.m.: Daniele Zuddas (University of Trieste), Compact topological 4-manifolds are finitely presentable
Abstract: Compact PL manifolds can be determined by a finite data set, that is a triangulation. On the other hand, compact topological 4-manifolds that are known to be not PL arise as the result of infinite constructions such as Casson handles. So it is natural to ask whether compact topological 4-manifolds can be determined by a finite data set. In this talk we answer in the affirmative. I will try to make the talk as much accessible as possible. This is a joint work with Micheal Freedman.
at 4.30 p.m.: Bruno Martelli (University of Pisa), Shadows of 3- and 4-manifolds II
Abstract: A shadow is a two-dimensional cell complex designed to be thickened in 4 dimensions. This object, introduced by Turaev, communicates nicely with three facets of geometric topology that are quite distant from each other: that of smooth 4-manifolds, hyperbolic 3-manifolds, and quantum invariants. We will introduce shadows and focus mostly on the first two aspects, that is their relation with 4-manifolds and hyperbolic 3-manifolds.