math.DG gr-qc math-ph math.MG math.MP 51K10, 83C75 (Primary), 35J92, 35Q75, 49Q22, 53C21, 53C50
  (Secondary)
A nonlinear d'Alembert comparison theorem and causal differential calculus on metric measure spacetimes
Tobias Beran Mathias Braun Matteo Calisti Nicola Gigli Robert J. McCann Argam Ohanyan Felix Rott Clemens Sämann