A SUP PLUS INF INEQUALITY FOR SOME NONLINEAR ELLIPTIC-EQUATIONS INVOLVING EXPONENTIAL NONLINEARITIES

Let u be a solution of the equation -Δu = V(x) eu in a domain Ω ⊂ R2 where 0 ≤ a < V ≤ b and V is Lipschitz continuous. We prove that sup u can be controlled in terms of inf u. More precisely, supKu + infΩu ≤ C(a, b, K, Ω, ||∇ V||L∞) for any compact subset K⊂Ω. This extends an earlier result of Shafrir who obtained a similar conclusion when V≡1. © 1993 Academic Press. All rights reserved.