Here we shall study some nonlinear partial differential equations involving the complex hessian cfic) = (d2f/dz, a&) which are related to the theory of functions of several complex variables. Since 8 and a are defined independently of the choice of local coordinates, the forms in the equations are invariant under holomorphic mappings. Certain properties of the forms on the left-hand side of (l.l), (1.2), and (1.3) were discussed by Chern, Levine, and Nirenberg [4] for the case where f is a bounded, real, plurisubharmonic function. The approach here is to drop the assumption that f is real and plurisubharmonic and require instead that f is Y 3 . In C", the (1, 1)-form %f may be identified with the complex hessian (hi) so that (l.l), (1.2), and (1.3) are easily seen to be equivalent (respectively) to the following three conditions (1.1y rank c f i~) 5 p ,