Birkhoffian formulations of nonholonomic constrained systems

Only for some special nonholonomic constrained systems can a canonical Hamiltonian structure be realized. Based on a reduction of a nonholonomic system to a conditional holonomic system, a universal symplectic structure for a constrained system can be constructed in the framework of Birkhoffian generalization of Hamiltonian mechanics, which preserves symbiotic character among derivability from a variational principle, Lie algebra and symplectic geometry. Two examples are presented.