设f1和f2是二阶微分方程f′′+A(z)f=0的两个线性无关的解,其中A(z)是无穷级整函数且超级σ2(A)〈∞.令E=f1f2.文章研究了E的超级为无穷的Borel方向和零点聚值线之间的关系.所得结果推广并改进了文献[7]中的一个结果.
Let f1 and f2 be two linearly independent solutions of second order differential equations f″ +A(z)f= 0, whereA(z) is an entire function of order infinite and hyper order σ2 (A) 〈 ∞. Set E = f1f2. In this paper,we established a relation between a cluster ray of the zeros and the Borel direction of E with hyper order infinite, which improve a recent result by Huang Zhibo and Chen Zongxuan.