Invariants of loops of 2-spheres and diffeomorphisms of the 4-sphere
David T. GAY
University of Georgia
https://www.math.uga.edu/directory/people/david-gay
Date(s) : 03/10/2025 iCal
11h00 - 12h00
This is a report on joint work with David Gabai and Daniel Hartman in which we define invariants of homotopy classes of loops of embeddings of 2-spheres in connected sums of S^2xS^2’s and use this to study isotopy classes of diffeomorphisms of S^4. The essential issue is to look at Cerf, Hatcher-Wagoner, and Igusa’s work on similar problems in higher dimensions and see how much we can salvage in dimension 4.
Emplacement
Saint-Charles - FRUMAM (2ème étage)
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