Second Order Estimates and Regularity for Fully Nonlinear Elliptic   Equations on Riemannian Manifolds
  We derive a priori second order estimates for solutions of a class of fully nonlinear elliptic equations on Riemannian manifolds under some very general structure conditions. We treat both equations on closed manifolds, and the Dirichlet problem on manifolds with boundary without any geometric restrictions to the boundary except being smooth and compact. As applications of these estimates we obtain results on regularity and existence. 
Bo Guan
math.AP math.DG