研究了无穷级亚纯函数的迭代级Borel方向问题,证明了从原点出发的射线argz=θ是函数f(z)的P次迭代级为σ的Borel方向的一个充分必要备件.另外,由这个结果还证明了角域内存在迭代级Borel方向的一个充分条件.
This paper studies the Borel direction with iterated order of the meromorphic functions of infinite order, and proves a sufficient and necessary condition of a radial argz = θ being a Borel direction with p-iterated order σ of f(z). In addition, from the result, we can obtain a sufficient condition of existing Borel direction with iterated order in angular domain.