Lorenzo Dello Schiavo, IST Austria: Wasserstein geometry and Ricci curvature bounds for Poisson spaces (Oberseminar Mathematische Stochastik)
Wednesday, 22.11.2023 14:00 im Raum SRZ 216
Let Y be the configuration space over a complete and separable metric base space, endowed with the Poisson measure \pi. We study the geometry of Y from the point of view of optimal transport and Ricci-lower bounds. To do so, we define a formal Riemannian structure on P_1(Y), the space of probability measures over Y with finite first moment, and we construct an extended distance W on P_1(Y). The distance W corresponds, in our setting, to the Benamou--Brenier variational formulation of the Wasserstein distance. Our main technical tool is a non-local continuity equation defined via the difference operator on the Poisson space. We show that the closure of the domain of the relative entropy is a complete geodesic space, when endowed with W. We establish non-local infinite-dimensional analogues of results regarding the geometry of the Wasserstein space over a metric measure space with synthetic Ricci curvature bounded below. In particular, we obtain that: (a) the Ornstein?Uhlenbeck semi-group is the gradient flow of the relative entropy; (b) the Poisson space has Ricci curvature bounded below by 1 in the entropic sense; (c) the distance W satisfies an HWI inequality.
Base on joint work arXiv:2303.00398 with Ronan Herry (Rennes 1) and Kohei Suzuki (Durham)
Angelegt am Wednesday, 12.07.2023 09:55 von Anita Kollwitz
Geändert am Monday, 13.11.2023 14:00 von Anita Kollwitz
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