本文證明了六個廣義Li6nard系統極限環之存在性定理。這些定理可以與浪左芬定理共同應用 到廣義Lidnard系統極限環的矸究中。Li6nard系統目前在二階做分系統、生態系統和電子震盪中有 廣泛應用，因而本文的結果是非常有意義的。

Six theorems on the existence of limit cycles in the generalized Lienard system: dx/dt - —F(x), dy/dt = g(x) have been obtained. These theorems can be employed together with Zhang's theorem (1958, 1986) to discuss the existence of the uniqueness of limit cycles in the generalized Lienard system. The generalized Lienard system is now often used in the studies of quadratic differential systems, ecological systems, and oscillation.