关键词: 文法推断 逐步求精 启发规则

Abstract:

This paper first introduces the stepwise refining method for inferring context-free grammars, and discusses the important role owned by the recursive  concept in the context-free grammars. Secondly, it presents several rules to improve the stepwise refining method in order to decrease the times of inqu iring of the user by the research on the specialty of the recursive concept. These rules are also suitable for other methods for inferring context-free  grammars.

Key words: （grammatical inference;stepwise refining, heuristic rules）