Videos

Recent progress on geometric analysis and Riemannian geometry: Introducing various notions of distances between space-times

Presenter
October 25, 2024
Keywords:
  • mean curvature flow
  • Ricci flow
  • fully nonlinear flows
  • general relativity
  • mass
  • Ricci curvature
  • scalar curvature
  • sectional curvature
  • symmetry
  • Riemannian geometry
  • groups actions
  • minimal surfaces
  • stability
  • and index
MSC:
  • 35-XX - Partial differential equations
  • 49-XX - Calculus of variations and optimal control
  • optimization
  • 53-XX - Differential geometry
  • 58-XX - Global analysis
  • analysis on manifolds
  • 83-XX - Relativity and gravitational theory
Abstract
I will introduce the class of causally-null-compactifiable spacetimes that can be canonically converted into compact timed-metric spaces using the cosmological time function of Andersson-Galloway-Howard and the null distance of Sormani-Vega. This class of space-times includes future developments of compact initial data sets and regions exhausting asymptotically flat space-times. I will discuss various intrinsic notions of distance between such space-times and show that some of them are definite in the sense that they are equal to zero if and only if there is a time-oriented Lorentzian isometry between the space-times. These definite distances allow us to define notions of convergence of space-times to limit space-times that are not necessarily smooth. This is joint work with Christina Sormani.