Critical singular problems via concentration-compactness lemma

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 −div |x|−ap|∇u|p−2∇u +λ|x|−(a+1)p|u|p−2u = |x|−bq |u|q−2u+ f, (P) where x ∈ RN, 1