文章基本信息

标题：Controlled Pure Grammar Systems
本地全文：下载
作者：Alexander Meduna ; Petr Zemek
期刊名称：Journal of Universal Computer Science
印刷版ISSN：0948-6968
出版年度：2012
卷号：18
期号：14
页码：2024
出版社：Graz University of Technology and Know-Center
摘要：This paper discusses grammar systems that have only terminals, work in the leftmost way, and generate their languages under the regulation by control languages over rule labels. It establishes three results concerning their generative power. First, without any control languages, these systems are not even able to generate all context-free languages. Second, with regular control languages, these systems, having no more than two components, characterize the family of recursively enumerable languages. Finally, with control languages that are themselves generated by regularcontrolled context-free grammars, these systems over unary alphabets generate nothing but regular languages. In its introductory section, the paper gives a motivation for introducing these systems, and in the concluding section, it formulates several open problems.
关键词：controlled derivations; formal languages; pure grammar systems