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.