Pseudoconvexity of Level Sets

Abstract

We investigate the pseudoconvexity of level sets of the distance function. First, we show the formula of \cite{Li17} for the Diederich--Fornæss index can be extended to characterize pseudoconvexity. This extension implies that the rate of change of the Levi form is nonincreasing at weakly pseudoconvex points. Additionally, we demonstrate that perturbing the distance function by a factor of $e^{-t|z|^2}$ ensures all level sets sufficiently close to the boundary are strongly pseudoconvex for all $t>0$.