Critical singular problems via concentration-compactness lemma

Abstract

In this work we consider existence and multiplicity results of nontrivial solutions for a class of quasilinear degenerate elliptic equations in RN of the form (P)−div[|x|−ap|∇u|p−2∇u]+λ|x|−(a+1)p|u|p−2u=|x|−bq|u|q−2u+f, where x∈RN, 1<p<N, q=q(a,b)≡Np/[N−p(a+1−b)], λ is a parameter, 0⩽a<(N−p)/p, a⩽b⩽a+1, and f∈(Lbq(RN))∗. We look for solutions of problem (P) in the Sobolev space Da1,p(RN) and we prove a version of a concentration-compactness lemma due to Lions. Combining this result with the Ekeland's variational principle and the mountain-pass theorem, we obtain existence and multiplicity results.