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Normal forms for contextual grammars
Andrzej Ehrenfeucht,Gheorghe Paun,Grzegorz Rozenberg +2 more
- pp 79-95
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Two normal form theorems for contextual grammars with regular choice are given, one concerning the (dyna mic) use of productions in derivations when a contextual grammar is executed in the external mode and the other concerned the (static) relationships between the productions.Abstract:
Two normal form theorems for contextual grammars with regular choice are given. The first one concerns the (dyna mic) use of productions in derivations when a contextual grammar is executed in the external mode. The second one concerns the (static) relationships between the productions and so it applies to both the external and the internal execution of contextual gram mars. Using the first normal form, a new (more elegant) proof of the linearity of the external languages of contextual grammars with regular choice is given.read more
Citations
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Book ChapterDOI
Contextual grammars and formal languages
TL;DR: The chapter by S. Marcus in this handbook gives a lucid account of the motivation behind contextual grammars from the natural point of view.
Journal ArticleDOI
On computational complexity of contextual languages
TL;DR: It is shown that all the three basic non-context-free constructions in natural languages, that is, multiple agreements, crossed agreements, and duplication, can be realized using this type of grammars and that these languages are parsable in polynomial time.
Journal ArticleDOI
On some classes of contextual grammars
TL;DR: A restricted version of depth-first contextual grammars, which depends on length of the inserting contexts, is considered, which gives a solution to the open problem P14 listed in [8].
Journal ArticleDOI
The linear landscape of external contextual languages
TL;DR: A characterization of linear languages and a whole landscape of sublinear families is obtained by restricting the contexts to be one-sided (only left-sided or only right-sided) and a characterization of regular languages — here the subregular landscape reduces to two families.
Journal ArticleDOI
On The Computational Complexity of Marcus Contextual Languages
TL;DR: It is proved that the family of languages generated by external contextual grammars with context-free selection contains only polynomial time parsable languages.
References
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Book
Marcus Contextual Grammars
Gheorghe Paun,Gheorghe Pun +1 more
TL;DR: 1. Origin and Motivation, Formal Language Theory Prerequisites, and A Generalization: n-Contextual Grammars.