Calendar
Tuesday, February 25, 2025
| Time | Items |
|---|---|
| All day |
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| 4:00pm |
02/25/2025 - 4:00pm The primary theme of this talk is geodesics. First I’ll introduce the Calculus of Variations and explain the variational approach to geodesics from Riemannian geometry. A novel result on the length of the shortest closed geodesic on 2-spheres will be presented. Next, I’ll consider these ideas in a data setting, where data diffusion has been a powerful tool for studying manifold geometry. I’ll discuss NeuralFIM, a diffusion-based method that learns a differentiable representation of the data, allowing for computation of the Fisher Information Metric (FIM). One can then use this Riemannian metric to compute volumes and geodesics on the data manifold. NeuralFIM is joint work with the Krishnaswamy Lab. Location:
LOM 215
02/25/2025 - 4:00pm It is known that the systole function, defined to be the length of a shortest closed geodesic, is topologically Morse on the moduli space of Riemann/hyperbolic surfaces, proved by Hugo Akrout. However, Morse theory cannot be applied as the function is not differentiable and the base space is noncompact.
We construct a family of weighted exponential averages of all geodesic-length functions, and show that they are Morse on the Deligne-Mumford compactification of the moduli space. We will also characterize the critical points and Morse indices, and from certain properties of them we may find conclusions on the homology of the moduli space by Morse theory.
Location:
KT 207
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