On 21 and 22 May 2025, for the cycle “Crossings - Math Seminars”, Gérard Besson (Université Grenoble Alpes) will give the following talks:
#1
Technical Seminar: On the intrinsic geometry of horospheres in negative curvature
Abstract: There are classical results showing that if a negatively closed manifold has its horospheres of constant mean curvature then it is locally symmetric. Here we shall present a rigidity result involving the intrinsic Riemannian structure of these horospheres. More precisely if one of them is flat than the closed manifold is locally real hyperbolic.
Date and time: Wednesday 21 May, at TBA
Place: TBA - Università di Milano-Bicocca
Time and place of the event will be announced shortly
#2
Math Forum: Some curious open manifolds
Abstract: We shall describe the construction of an open $3$-manifold called the Whitehead Manifold. The construction uses a knot in $S^3$ and variations on it produce a non countable family of strange objects. Very little is known on the Riemannian geometry and the analysis that they carry and we may mention some questions. They also play an important role in dimension 4. The construction will be presented with easy tools.
Date and time: Thursday 22 May, at 3 pm
Place: U4-08 Building (Room Sironi), Piazza della Scienza, 4 - University of Milano-Bicocca
A coffee break will follow
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