Talk page

Title:
Lorentzian length spaces

Speaker:
Clemens Saemann

Abstract:
We introduce an analogue of the theory of length spaces into the setting of Lorentzian geometry and causality theory. The role of the metric is taken over by the time separation function, in terms of which all basic notions are formulated. In this way we recover many fundamental results in greater generality, while at the same time clarifying the minimal requirements for and the interdependence of the basic building blocks of the theory. A main focus of this work is the introduction of synthetic curvature bounds, akin to the theory of Alexandrov and CAT(k)-spaces, based on triangle comparison. Applications include Lorentzian manifolds with metrics of low regularity, closed cone structures, and warped products of a line with a (Riemannian) length space. Moreover, an application to the low regularity (in)-extendibility of spacetimes is given and if time permits we give an outlook on a notion of convergence of such spaces.

Link:
http://scgp.stonybrook.edu/video_portal/video.php?id=4085

Workshop:
Simons- Workshop: Convergence and Low Regularity in General Relativity