摘要
<正> 1 FRD_辖区设∑是一个有限字母表,∑~*表示由∑生成的自由幺半群,其子集合称为语言。由语言L?
A languafes L is called RF__right disjunctive, if there exists a right dense lan-guage D such that every R_L__class [X]_L conttains only a finite number of words in D. In or-der to investigate it, we introduced and discussed the FRD_domains in this paper. When |∑|≥2, D is uniformly right dense iff D is an FRD__domain and D is a strongly right denselanguage. By the way, an infinite hierarchy of right dense languages is obtained.
出处
《纯粹数学与应用数学》
CSCD
1991年第1期5-10,共6页
Pure and Applied Mathematics
