研究非自治Birkhoff系统的Poisson理论。建立了系统的Poisson条件,证明了在一定条件下可由已知第一积分得到新的第一积分。由于条件比以往同类结果更宽松,因此,结果更具普遍性。文末举例予以说明。
The Poisson theory of a non-autonomous Birkhoffian system is studied. We have established the Poisson condition for the system and proved the proposition that under certain conditions a new first integral can be obtained by a known first integral. As the condition is looser than similar results, the resulting theorem is more universal. Three examples are given to illustrate the application of the results.