Mauricio Bustamante: "Symmetries of exotic negatively curved manifolds"

mercredi 27 févr. 2019, 14:00 → 15:00 Europe/Paris

435 (UMPA)

Let N be a smooth manifold that is homeomorphic but not diffeomorphic to a closed hyperbolic manifold M. To what extent does N admit as much symmetry as M?. In this talk, I wil show that it's possible to find N with maximal symmetry, i.e. Isom(M) acts on N by isometries with respect to some negatively curved metric on N. For these examples, Isom(M) can be made arbitrarily large. On the other hand, one can also find N with little symmetry, i.e. no subgroup of Isom(M) of “small” index acts by diffeomorphisms of N. This is joint work with Bena Tshishiku.