%0 Journal Article
%T Analysis of Valid Closure Property of Formal Language
%A Wenyu Chen
%A Xiaobin Wang
%A Xiaoou Cheng
%A Shixin Sun
%J Journal of Computers
%D 2010
%I Academy Publisher
%R 10.4304/jcp.5.2.322-329
%X This paper focuses on the basic operations of Chomsky¡¯s languages. The validity and the effectiveness of some closure operations, such as union operator, product operator and Kleene Closure operator, are discussed in detail. The crosstalk problems in Context-Sensitive Languages (CSL) and Phrase Structure Languages (PSL) are analyzed, and a valuable method to solve this problem is presented by suing the alphabet of the operating languages. In addition, according to the valid closure property of regular languages (RL), a simple method to create a regular expression (RE) is proposed. The closure property of the permutation operator in Context-Free Languages (CFL) is proved and tested. In conclusion, by using our proposed methods, the exact type of a given language can be proved theoretically. By the way, the grammar to produce complex language can be created easy. Finally ,the constructing ¦Å-NFA with the closure property is proved.
%K language operation
%K valid closure property
%K crosstalk
%K context-free permutation
%U http://ojs.academypublisher.com/index.php/jcp/article/view/633