7 May 2026
3:30pm CEST
ROYA MOHAYAEE
(Sorbonne University, France)
Title: Optimal Transport theory and its applications in cosmology
Abstract: I will begin with a concise review of the fundamental ideas underlying optimal transport theory, before illustrating how these concepts naturally emerge in cosmological contexts and provide a powerful framework for addressing the problem of cosmological reconstruction. I will then highlight how optimal transport extends beyond its analytical utility in handling big data, and demonstrate intriguing connections with certain theories of modified gravity.
4 June 2026
3:30pm CEST
MIGUEL SÁNCHEZ
(University of Granada, Spain)
Title: Globally hyperbolic spacetimes-with-timelike-boundary: global splitting, asymptotically AdS spacetimes and null-convexity
Abstract: Globally hyperbolic spacetimes with a timelike boundary model spacetimes with naked singularities distributed on a timelike hypersurface, potentially admitting conditions on both the boundary and a Cauchy hypersurface. Typically, the boundary can serve as: (1) a cut-off for the system under consideration, or (2) a conformal completion of the spacetime, as in the case of asymptotically Anti-de Sitter spacetimes.
First, we will review some of their general properties, including those related to causality, the existence of global orthogonal splittings, and the relationship between the properties of the boundary and the interior of the spacetime. Then, we will focus on the null-convexity of the boundary. This is a natural assumption satisfied by asymptotically AdS spacetimes, which implies that the interior of the spacetime retains most of the geometric properties of the boundaryless case, such as being causally simple with a Hausdorff space of lightlike geodesics.
Based in joint work with L. Aké and JL. Flores (arxiv: 1808.04412) and with J. Herrera (arxiv: 2506.09032).