Nambu-Lie group actions.
New trends in mechanics. I. Generalized differential variational principles in rational mechanics.
New variational principle and duality for an abstract semilinear Dirichlet problem
A new variational principle and duality for the problem Lu = ∇G(u) are provided, where L is a positive definite and selfadjoint operator and ∇G is a continuous gradient mapping such that G satisfies superquadratic growth conditions. The results obtained may be applied to Dirichlet problems for both ordinary and partial differential equations.
Normal Modes for Nonlinear Hamiltonian Systems.