0000000000515393
AUTHOR
Giuseppe Cordaro
showing 2 related works from this author
Three solutions for a perturbed Dirichlet problem
2008
Abstract In this paper we prove the existence of at least three distinct solutions to the following perturbed Dirichlet problem: { − Δ u = f ( x , u ) + λ g ( x , u ) in Ω u = 0 on ∂ Ω , where Ω ⊂ R N is an open bounded set with smooth boundary ∂ Ω and λ ∈ R . Under very mild conditions on g and some assumptions on the behaviour of the potential of f at 0 and + ∞ , our result assures the existence of at least three distinct solutions to the above problem for λ small enough. Moreover such solutions belong to a ball of the space W 0 1 , 2 ( Ω ) centered in the origin and with radius not dependent on λ .
Three periodic solutions for perturbed second order Hamiltonian systems
2009
AbstractIn this paper we study the existence of three distinct solutions for the following problem−u¨+A(t)u=∇F(t,u)+λ∇G(t,u)a.e. in [0,T],u(T)−u(0)=u˙(T)−u˙(0)=0, where λ∈R, T is a real positive number, A:[0,T]→RN×N is a continuous map from the interval [0,T] to the set of N-order symmetric matrices. We propose sufficient conditions only on the potential F. More precisely, we assume that G satisfies only a usual growth condition which allows us to use a variational approach.