Issues Regarding ε in Formal Language and Automata Theory
形式语言与自动机中关于ε的一些问题

The paper discussed some issues regarding blank string e in the formal language and automata theory.After analysis of the influence of production e on grammar and language classification,the paper discussed the effect of starting symbol S and the starting state qo from the perspective of grammer and infinite state and proposed a simple method to increase language or decrease sentence ε.The paper also proposed a new method to transit ε-NFA to NFA after studying the essence of ε state transition function of ε-NFA.The method is:first transit ε-NFA to formal grammar and eliminate production ε and single production.After that,regular grammar was obtained.Then transited regular grammar to NFA.Examples were given to support the discussion.