设A(z)是方程f″+P(z)f=0的非零解,其中P(z)是n次多项式,B(z)是一个超越整函数且满足ρ(B)≤1/2.那么方程f″+Af′+Bf=0的每一个非零解都是无穷级.并且方程f″+A(z)f=0两个线性无关解乘积的零点序列收敛指数为无穷.
Let A(z) be a nontrivial solution of f" + P(z)f = 0, where P(z) is a polynomial and let B(z) be a transcendental entire function of order p≤1/2. Then every nontrivial solution of f" + A(z)f′ + B(z)f = 0 is of infinite order. Moreover, the exponent of convergence of zero-sequence of the product of two linearly independent solutions of f″ + A(z)f = 0 is of infinite.