本文研究了平面上的亚纯函数的奇异方向,利用Tsuji’s的第二基本定理和几个已有的关于函数增长性估计的引理,证明了平面上的零级亚纯函数至少存在一条T方向,这种方向直接以特征函数为比较函数,克服了Borel方向的定义中关于增长级不能为零的限制.
In this paper, the authors consider a singular direction of an meromorphic function. By using the Tsuji's version of the Second Fundamental Theorem and several growth lemmas established earlier, we discuss the existence of a new singular direction for zero order meromorphic function f, namely, a T direction for f, for which the characteristic function T(r,f) is used as a comparison function. Recalling the definition of the Borel direction, this characteristic function is effective only for the finite order functions, so the idea of the T direction could remove the difficulties in the case of zero order functions.