A fundamental inequality of algebroidal function (Q1938237)

The paper under review deals with some relations involving algebroidal functions. The authors prove a fundamental inequality of the angular domain for algebroidal functions using a new mapping of Ahlfors covering surfaces. In fact, the fundamental inequality of Theorem 1.1 of the paper under review is an extension of an inequality proved by \textit{M. Tsuji} [Potential theory in modern function theory. Tokyo: Maruzen Co., Ltd. (1959; Zbl 0087.28401)]. It be can be regarded as a fundamental tool in the field of value distribution theory of algebroidal functions because it can be used to investigate the singular direction.