“…The microscopic convexity principle, with applications in geometric equations on manifolds, has been established in [2] for the very general fully nonlinear elliptic and parabolic operators of second order. Guan, Spruck and Xiao [9] point out that the asymptotic Plateau problem for finding a complete strictly locally convex hypersurface is reduced to the Dirichlet problem for a fully nonlinear equation, a special form of which is the k−Hessian equation, see Corollary 1.11, [9] and they have proved the existence of such hypersurface, it is especially interesting that they have proved that, if ∂Ω is strictly (Euclidean) star-shaped about the origin, so is the unique solution, see Theorem 1.5, [9]. For the k-Hessian equation with k = 2, n = 3, the power convexity for Dirichlet problem of equation (1.1) with f = 1, and log-convexity for the eigenvalue problem have been studied in [16,17], see also [18].…”