External Lecturer:
Mathias Braun (EPFL)
Course Type:
PhD Course
Academic Year:
2025-2026
Period:
December 2025 - January 2026
Duration:
20 h
Description:
Abstract. Lorentzian geometry is the mathematical foundation of Einstein's theory of general relativity, which explains gravity as a manifestation of spacetime curvature (unlike Newton’s theory, which treats gravity as a force). This course has two objectives. First, we give an overview of classical concepts from Lorentzian geometry, encompassing e.g. length, geodesics, causality theory, curvature, Einstein's equations, black hole models, Hawking-Penrose incompleteness theorems, the splitting theorem, etc. Second, we complement this exposition with an introduction to recent and vibrant research on these aspects through the lens of metric geometry and optimal transport, including e.g. metric measure spacetimes, Lorentz-Wasserstein distance, timelike curvature-dimension condition, needle decomposition, Sobolev calculus, comparison theory, Lorentz-Gromov-Hausdorff convergence, etc. Where appropriate, we will highlight new methods to establish (and generalize) classical results.
The precise focus will be adapted to the background and interest of the audience.
References
The following standard textbooks will be the basis for the classical theory.
[1] S. Hawking, G. F. R. Ellis. The large-scale structure of space-time (1973).
[2] B. O'Neill. Semi-Riemannian geometry (1983).
[3] R. M. Wald. General relativity (1984).
[4] J. K. Beem, P. E. Ehrlich, K. L. Easley, Global Lorentzian geometry (1996).
To get an inspiration about recent research, the following survey papers are recommended as a starter.
[5] F. Cavalletti, A. Mondino. A review of Lorentzian synthetic theory of timelike Ricci curvature bounds (2022).
[6] C. Sämann. A brief introduction to non-regular spacetime geometry (2024).
[7] R. J. McCann. Trading linearity for ellipticity: a nonsmooth approach to Einstein’s theory of gravity and the Lorentzian splitting theorems (2025).
[8] M. Braun. New perspectives on the d'Alembertian from general relativity. An invitation (2025).
Research Group:
Location:
A-133
