<正> 自從F. Tricomi在1923年發表了一篇關於混合型微分方程的論文以後,各國數學家繼續在這方面工作的,不乏其入;尤其是蘇聯數學家,近年來在這方面有極其光輝的貢獻。過去所考慮的問題,都是兩個域的問題,現在我們要考慮的,是多個域的混合型問題。我們考慮下面兩個方程的定解問題:

In this note we deal with firstly the Tricomi problem of the equation by the method of and Then we solved Cauchy's problem and the third problem of the equation in its hyperbolic domain. The method is based on the Poisson formula of the generalized Euler-Poisson equation.