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$% V. Ferone and B. Messano, A symmetrization result for nonlinear elliptic equations, Rev. Mat. Complut. 17 (2004), 261–276.%$

A Symmetrization Result for Nonlinear Elliptic Equations

Vincenzo FERONE and Basilio MESSANO
Dipartimento di Matematica e Applicazioni “R.Caccioppoli”
Università di Napoli “Federico II”
Complesso Univ. Monte S. Angelo
Via Cintia - 80126 Napoli Italy
Dipartimento di Matematica e Applicazioni “R.Caccioppoli”
Università di Napoli “Federico II”
Via Claudio, 21 - 80125 Napoli Italy

Received: February 21, 2003
Accepted: September 30, 2003

ABSTRACT

We consider a solution u of the homogeneous Dirichlet problem for a class of nonlinear elliptic equations in the form A(u) = g(x,u) + f, where the principal term is a Leray-Lions operator defined on W01 ,p (_O_). The function g(x,u) satisfies suitable growth assumptions, but no sign hypothesis on it is assumed. We prove that the rearrangement of u can be estimated by the solution of a problem whose data are radially symmetric.

Key words: symmetrization, rearrangement, nonlinear elliptic PDE’s.
2000 Mathematics Subject Classification:
35J65, 35B45.