Existence of CMC and constant areal time foliations in T^2 symmetric   spacetimes with Vlasov matter
  The global structure of solutions of the Einstein equations coupled to the Vlasov equation is investigated in the presence of a two-dimensional symmetry group. It is shown that there exist global CMC and areal time foliations. The proof is based on long-time existence theorems for the partial differential equations resulting from the Einstein-Vlasov system when conformal or areal coordinates are introduced. 
Hakan Andreasson, Alan D. Rendall, Marsha Weaver