A shrinking lemma for random forbidding context languages
نویسندگان
چکیده
منابع مشابه
Ogden’s Lemma for Random Permitting and Forbidding Context Picture Languages and Table-Driven Context-Free Picture Languages
Random context picture grammars are used to generate pictures through successive refinement. There are three important subclasses of random context picture grammars, namely random permitting context picture grammars, random forbidding context picture grammars and table-driven context-free picture grammars. These grammars generate the random permitting context picture languages, random forbiddin...
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Context-free languages (CFLs) are highly important in computer language processing technology as well as in formal language theory. The Pumping Lemma is a property that is valid for all context-free languages, and is used to show the existence of non context-free languages. This paper presents a formalization, using the Coq proof assistant, of the Pumping Lemma for context-free languages.
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Seki et al. (1991) proved a rather weak pumping lemma for multiple context-free languages, which says that any infinite m-multiple context-free language contains a string that is pumpable at some 2m substrings. We prove a pumping lemma of the usual universal form for the subclass consisting of well-nested multiple context-free languages. This is the same class of languages generated by non-dupl...
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Motivated by biomolecular computing, forbidding-enforcing systems (fe-systems) were first used to define classes of languages (fefamilies) based on boundary conditions. This paper presents a new model of fe-systems in which fe-systems define single languages (fe-languages) based on forbidden and enforced subwords. The paper characterizes wellknown languages by fe-systems, investigates the relat...
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 2000
ISSN: 0304-3975
DOI: 10.1016/s0304-3975(98)00160-1