8 apr 2025 -- 14:30
Sala Riunioni, Dipartimento di Matematica, Pisa
Abstract.
We show that there exist two embedded 2-spheres in the 4-sphere which are separated by an integer homology 3-sphere Y (i.e., a manifold with the same integer homology of the 3-sphere), but not by the standard 3-sphere. This is joint work with Marco Golla.