On the periodicity of regular languages

Kai Hwang
1979 Information and Control  
A subclass of regular languages called periodic languages and the corresponding finite automata having nontrivial periodid, structure are characterized in this paper. Canonical forms of the regular expressions representing such periodic languages are presented. A systematic procedure to determine the periodicity of any given regular expression is devised through a differential approach. Closure properties of periodic languages are found. Relationships between period!c languages and other
more » ... ses of regular languages, such as finite sets and definite languages, are established. We demonstrate a periodic formation of the grammatical production rules for periodic languages. The reducibility of periodic automata and languages is also studied.
doi:10.1016/s0019-9958(79)90394-2 fatcat:bwafmd5vybhghm73zaoiktdfwu