Journal ArticleDOI
On some classes of contextual grammars
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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].Abstract:
In this paper, we introduce some new variants of contextual grammars and investigate their generative power. We'consider a restricted version of depth-first contextual grammars, which depends on length of the inserting contexts. Using this variant, we give a solution to the open problem P14 listed in [8]. We also introduce random context contextual grammars and compare its generative power with the families IC , ICC , EC , ECC , TC . Time-varying contextual grammars are introduced which resemble time-varying grammars. We compare the generative power of this variant with the families of internal, external, total, matrix, and programmed contextual grammars.read more
Citations
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Journal Article
End-marked maximal depth-first contextual grammars
TL;DR: In this paper, the authors introduce two new classes of internal contextual grammars, called end-marked maximal depth-first and inner end-marked maximal depthfirst contextual Grammars.
Journal ArticleDOI
On the Trade-off Between Ambiguity and Complexity in Contextual Languages
TL;DR: The notion of a pseudo inherently ambiguous language with respect to two complexity measures is introduced and investigated and an open problem from [15] is solved in this framework.
References
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BookDOI
Handbook of Formal Languages
Grzegorz Rozenberg,Arto Salomaa +1 more
TL;DR: This first handbook of formal languages gives a comprehensive up-to-date coverage of all important aspects and subareas of the field.
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.
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 Article
On Representing RE Languages by One-Sided Internal Contextual Languages.
TL;DR: It is proved that each recursively enumerable language L can be written in the form L — cutd(L' fl R), where L' is a language generated by a one-sided internal contextual grammar witli context-free choice, R is a regular language, and cutd is the operation which removes the prefix bounded by the special symbol d.
Book
Normal forms for contextual grammars
TL;DR: 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.