Existence et non existence de tores invariants par des difféomorphismes symplectiques
Existence of conservation laws in nilpotent case.
Existence of four solutions of some nonlinear Hamiltonian system.
Existence of homoclinic orbits for Hamiltonian systems with superquadratic potentials.
Existence of infinitely many homoclinic orbits in hamiltonian systems.
Existence of periodic solutions of linear Hamiltonian systems with sublinear perturbation.
Existence of solutions and of multiple solutions for nonlinear nonsmooth periodic systems
In this paper we examine nonlinear periodic systems driven by the vectorial -Laplacian and with a nondifferentiable, locally Lipschitz nonlinearity. Our approach is based on the nonsmooth critical point theory and uses the subdifferential theory for locally Lipschitz functions. We prove existence and multiplicity results for the “sublinear” problem. For the semilinear problem (i.e. ) using a nonsmooth multidimensional version of the Ambrosetti-Rabinowitz condition, we prove an existence theorem...
Existence of solutions for a nonlinear algebraic system.
Existence of solutions for a nonlinear discrete system involving the -Laplacian
The existence of solutions for boundary value problems for a nonlinear discrete system involving the -Laplacian is investigated. The approach is based on critical point theory.
Existence of solutions to a Hamiltonian system without convexity condition on the nonlinearity.
Existence of star-products on exact symplectic manifolds
It is shown that if a manifold admits an exact symplectic form, then its Poisson Lie algebra has non trivial formal deformations and the manifold admits star-products. The non-formal derivations of the star-products and the deformations of the Poisson Lie algebra of an arbitrary symplectic manifold are studied.
Explicit Solutions of Classical Generalized Toda Models.
Exploding orbits of holomorphic structures.
Extensions of symplectic groupoids and quantization.