Geometric Group Theory Seminar - Daniel Ruberman

Ohio State Garden of Constants
October 17, 2024
1:50PM - 2:50PM
SM1138

Date Range
2024-10-17 13:50:00 2024-10-17 14:50:00 Geometric Group Theory Seminar - Daniel Ruberman Daniel RubermanBrandeis UniversityTitleHomotopy properties of diffeomorphism groups and spaces of positive scalar curvature on 4-manifoldsAbstractWe show that the higher homotopy groups of the diffeomorphism group of a smooth 4-manifold can have infinitely generated free abelian summands. The same applies to the homology of the Torelli subgroup and of its classifying space. We show that the homotopy groups of the space of positive scalar curvature metrics on a large connected sum of S^2 x S^2's can have infinitely generated free abelian subgroups. This is all joint work with Dave Auckly  SM1138 Department of Mathematics math@osu.edu America/New_York public

Daniel Ruberman
Brandeis University

Title
Homotopy properties of diffeomorphism groups and spaces of positive scalar curvature on 4-manifolds

Abstract
We show that the higher homotopy groups of the diffeomorphism group of a smooth 4-manifold can have infinitely generated free abelian summands. The same applies to the homology of the Torelli subgroup and of its classifying space. We show that the homotopy groups of the space of positive scalar curvature metrics on a large connected sum of S^2 x S^2's can have infinitely generated free abelian subgroups. This is all joint work with Dave Auckly
 

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