二阶微分方程解的下级与型（英文）

The main purpose of this paper is to study the lower order and type of second order differential equation w"(z)-A(z)w=0,where A(z)is a polynomial.In the case of A(z)=a_dz~d,the authors prove that the lower order and the type of all non-trivial solutions w of w"(z)-A(z)w=0 are equal to(d+2)/2 and(2(|a_d|)~(1/2))/(d+2)respectively.In the case of A(z)=a_dz~d+a_(d-1)z~(d-1)+…a_1z+a_0,a_d0,a_(d-1)0,…,a_1≥0,a_0≥0,the authors prove that the lower order of all non-trivial solutions w of w"(z)-A(z)w=0 is(d+2)/2.