Semilinear elliptic problems near resonance with a nonprincipal eigenvalue

We consider the Dirichlet problem for the equation − u = λu±f (x,u)+h(x) in a bounded domain, where f has a sublinear growth and h ∈ L2.We find suitable conditions on f and h in order to have at least two solutions for λ near to an eigenvalue of − . A typical example to which our results apply is when f (x,u) behaves at infinity like a(x)|u|q−2u, with M >a(x)>δ>0, and 1