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Current Schedule
This Week
- Wednesday September 23 at 4:00 PM in RH 104
- Paul Kirk (IU), “A genus 2 symplectic surface in an exotic CP^2#2 bar CP^2 with simply connected complement”
I'll outline how to construct a minimal symplectic 4-manifold homeomorphic but not diffeomorphic to CP^2 blown up twice (a' la Akhmedov-Park) and show that it contains a genus two symplectic surface with simply connected complement. As an application, I'll show how to easily fill large regions in the geography/botany problem for simply connected 4-manifolds.
Upcoming Weeks
- Wednesday September 30 at 4:00 PM in RH 104
- Eleftherios Chatzitheodoridis (VCU), “Trees associated with unitary partition complexes”
In a recent paper, Heuts and Moerdijk develop a poset of trees whose classifying space is homotopy equivalent to the n-th partition complex, that is, the classifying space of the poset of partitions of a set with n elements. The latter poset features in work of Arone, Dwyer, and Lesh, and it finds a unitary analog introduced by Arone and Lesh. In joint work with Julie Bergner, Pedro Brunialti Lima de Andrade, and Josh Turner, we develop a topological poset of trees whose classifying space is homotopy equivalent to the n-th unitary partition complex, that is, the classifying space of the topological poset of partitions of n-dimensional complex space in pairwise orthogonal subspaces. Our work builds on the study of unitary partition complexes by Bergner, Joachimi, Lesh, Stojanoska, and Wickelgren, and it also entails some new results in the theory of topological categories that may be of independent interest.
- Wednesday October 21 at 4:00 PM in RH 104
- Adam Levine (Duke)