On the descriptional complexity of scattered context grammars
نویسندگان
چکیده
منابع مشابه
On the descriptional complexity of scattered context grammars
This paper proves that every recursively enumerable language is generated by a scattered context grammar with no more than four nonterminals and three non-context-free productions. In its conclusion, it gives an overview of the results and open problems concerning scattered context grammars and languages.
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Recently, it has been shown that every recursively enumerable language can be generated by a scattered context grammar with no more than three nonterminals. However, in that construction, the maximal number of nonterminals simultaneously rewritten during a derivation step depends on many factors, such as the cardinality of the alphabet of the generated language and the structure of the generate...
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This paper presents some new results concerning the descriptional complexity of partially parallel grammars. Specifically, it proves that every recursively enumerable language is generated (i) by a four-nonterminal scattered context grammar with no more than four non-context-free productions, (ii) by a two-nonterminal multisequential grammar with no more than two selectors, or (iii) by a three-...
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The descriptional complexity of semi-conditional grammars is studied. A proof that every recursively enumerable language is generlji";'I":ff f iru*::?H:"ffi Xl,?li".ffi f iJ,,-,T?,ll,J"'"'n'"
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 2009
ISSN: 0304-3975
DOI: 10.1016/j.tcs.2008.10.017