Symmetrization with respect to the anisotropic perimeter and   applications
  In this paper we introduce a new type of symmetrization, which preserves the anisotropic perimeter of the level sets of a suitable concave smooth function, in order to prove sharp comparison results for solutions of a class of homogeneous Dirichlet fully nonlinear elliptic problems of second order and for suitable anisotropic Hessian integrals. 
Francesco Della Pietra and Nunzia Gavitone
math.AP