On the Global Evolution Problem in 2+1 Gravity

Lars Andersson

Abstract: We prove global existence in constant mean curvature gauge for the evolution problem for 2+1 dimensional vacuum Einstein equations, with data given on a compact orientable surface. A reduction of the 2+1 vacuum Einstein equations gives a Hamiltonian system on the cotangent bundle of Teichmuller space and this plays a central role in the proof. The 3+1 dimensional Einstein vacuum equations lead, in the presence of a spatial Killing field, to 2+1 dimensional Einstein equations with matter. Therefore the 2+1 vacuum case can be viewed as a test case for the 3+1 dimensional, 1 Killing field, evolution problem.