摘要
We investigate sufficient conditions (theorem 1) for the non-existence of periodic solutions of ecluatlon (2. 1 ) with P = 0 and sufficient, conditions (theorem 2) for existencc of periodic solutions of equation (1. 1. 1 ).
We investigate sufficient conditions (theorem 1) for the non-existence of periodic solutions of ecluatlon (2. 1 ) with P = 0 and sufficient, conditions (theorem 2) for existencc of periodic solutions of equation (1. 1. 1 ).
