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
Contextual Grammars with Subregular Choice
TL;DR: The hierarchy of language families of contextual languages which is obtained by the use of nilpotent, combinational, definite, regular suffix closed, and regular commutative languages as choice languages is determined.
Journal ArticleDOI
Internal Contextual Grammars for Mildly Context-Sensitive Languages
Lakshmanan Kuppusamy,Lakshmanan Kuppusamy,Shankara Narayanan Krishna,Rama Raghavan,Carlos Martín-Vide +4 more
TL;DR: It is shown that the three basic non-context-free constructions in natural languages can be realized upon using all such variants, and that the membership problem for the family of absorbing right context contextual languages is decidable by a polynomial time algorithm.
Book ChapterDOI
End-Marked maximal depth-first contextual grammars
TL;DR: It is shown that the three basic non-context-free constructions in natural languages can be realized upon using these variants and the family of languages generated by end-marked maximal depth-first grammars contains non-semilinear languages.
Journal Article
Semi-bracketed contextual grammars
TL;DR: A new class of fully bracketed contextual grammars is introduced, called the semi-bracketed contextual Grammars, where the selectors can also be non-minimally Dyck covered language and the tree structure to the derived strings is still preserved in this variant.
Book ChapterDOI
Marcus Contextual Grammars
TL;DR: The decade of the 1950s has witnessed great steps forward in the systematic investigation of natural languages by means of mathematical tools as mentioned in this paper, with the publication of Chomsky's pioneering book [5] in 1957, the generative approach emerged, while, at the same time, research done within the Russian school of Mathematics gave a new start in the development of analytical mathematical models of language.
References
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Journal ArticleDOI
On contextual grammar forms
TL;DR: The grammatical families of all languages generated by simple contextual grammars which are obtained by (strict) interpretations of a simple contextual grammar are investigated in this paper, and their hierarchies and their closure properties with respect to the AFL-operations are studied.