Lorentzian length spaces

M Kunzinger, C Sämann - Annals of global analysis and geometry, 2018 - Springer
We introduce an analogue of the theory of length spaces into the setting of Lorentzian
geometry and causality theory. The rôle of the metric is taken over by the time separation …

Optimal transport in Lorentzian synthetic spaces, synthetic timelike Ricci curvature lower bounds and applications

F Cavalletti, A Mondino - arXiv preprint arXiv:2004.08934, 2020 - arxiv.org
The goal of the present work is three-fold. The first goal is to set foundational results on
optimal transport in Lorentzian (pre-) length spaces, including cyclical monotonicity, stability …

Rényi's entropy on Lorentzian spaces. Timelike curvature-dimension conditions

M Braun - Journal de Mathématiques Pures et Appliquées, 2023 - Elsevier
For a Lorentzian space measured by m in the sense of Kunzinger, Sämann, Cavalletti, and
Mondino, we introduce and study synthetic notions of timelike lower Ricci curvature bounds …

Time functions on Lorentzian length spaces

A Burtscher, L Garcia-Heveling - Annales Henri Poincaré, 2024 - Springer
In general relativity, time functions are crucial objects whose existence and properties are
intimately tied to the causal structure of a spacetime and also to the initial value formulation …

Null distance and convergence of Lorentzian length spaces

M Kunzinger, R Steinbauer - Annales Henri Poincaré, 2022 - Springer
The null distance of Sormani and Vega encodes the manifold topology as well as the
causality structure of a (smooth) spacetime. We extend this concept to Lorentzian length …

A Lorentzian analog for Hausdorff dimension and measure

RJ McCann, C Sämann - Pure and Applied Analysis, 2022 - msp.org
We define a one-parameter family of canonical volume measures on Lorentzian (pre-)
length spaces. In the Lorentzian setting, this allows us to define a geometric dimension …

Hyperbolic angles in Lorentzian length spaces and timelike curvature bounds

T Beran, C Sämann - Journal of the London Mathematical …, 2023 - Wiley Online Library
Within the synthetic‐geometric framework of Lorentzian (pre‐) length spaces developed in
Kunzinger and Sämann (Ann. Glob. Anal. Geom. 54 (2018), no. 3, 399–447) we introduce a …

Generalized cones as Lorentzian length spaces: Causality, curvature, and singularity theorems

SB Alexander, M Graf, M Kunzinger… - arXiv preprint arXiv …, 2019 - arxiv.org
We study generalizations of Lorentzian warped products with one-dimensional base of the
form $ I\times_f X $, where $ I $ is an interval, $ X $ is a length space and $ f $ is a positive …

A synthetic null energy condition

RJ McCann - Communications in Mathematical Physics, 2024 - Springer
We give a simpler approach to Kunzinger and Sämann's theory of Lorentzian length spaces
in the globally hyperbolic case; these provide a nonsmooth framework for general relativity …

A nonlinear d'Alembert comparison theorem and causal differential calculus on metric measure spacetimes

T Beran, M Braun, M Calisti, N Gigli, RJ McCann… - arXiv preprint arXiv …, 2024 - arxiv.org
We introduce a variational first-order Sobolev calculus on metric measure spacetimes. The
key object is the maximal weak subslope of an arbitrary causal function, which plays the role …