Refer to the Hamiltonian system, first integrals of the Birkhoffian system can be found by using of the perfect differential method. Through these first integrals, the order of the Birkhoffian system can be reduced. T...Refer to the Hamiltonian system, first integrals of the Birkhoffian system can be found by using of the perfect differential method. Through these first integrals, the order of the Birkhoffian system can be reduced. Then according to the alternate of the coordinate, a kind of new partial differential operator was defined in order to hold the Birkhoff form. The result shows that the Birkhoffian system has generalized energy integrals and cyclic integrals. Furthermore, each integral can reduce the order of equations two degrees.展开更多
The Noether symmetry is an invariance of Hamilton action under infinitesimal transformations of time and the coordinates.The Lie symmetry is an invariance of the differential equations of motion under the transformati...The Noether symmetry is an invariance of Hamilton action under infinitesimal transformations of time and the coordinates.The Lie symmetry is an invariance of the differential equations of motion under the transformations.In this paper,the relation between these two symmetries is proved definitely and firstly for mechanical systems.The results indicate that all the Noether symmetries are Lie symmetries for Lagrangian systems meanwhile a Noether symmetry is a Lie symmetry for the general holonomic or nonholonomic systems provided that some conditions hold.展开更多
文摘Refer to the Hamiltonian system, first integrals of the Birkhoffian system can be found by using of the perfect differential method. Through these first integrals, the order of the Birkhoffian system can be reduced. Then according to the alternate of the coordinate, a kind of new partial differential operator was defined in order to hold the Birkhoff form. The result shows that the Birkhoffian system has generalized energy integrals and cyclic integrals. Furthermore, each integral can reduce the order of equations two degrees.
基金The project supported by the National Natural Science Foundation of China (19972010)
文摘The Noether symmetry is an invariance of Hamilton action under infinitesimal transformations of time and the coordinates.The Lie symmetry is an invariance of the differential equations of motion under the transformations.In this paper,the relation between these two symmetries is proved definitely and firstly for mechanical systems.The results indicate that all the Noether symmetries are Lie symmetries for Lagrangian systems meanwhile a Noether symmetry is a Lie symmetry for the general holonomic or nonholonomic systems provided that some conditions hold.
