A1 Refereed original research article in a scientific journal
Conjunctive grammars with restricted disjunction
Authors: Okhotin Alexander, Reitwiessner Christian
Publisher: ELSEVIER SCIENCE BV
Publication year: 2010
Journal: Theoretical Computer Science
Journal name in source: THEORETICAL COMPUTER SCIENCE
Journal acronym: THEOR COMPUT SCI
Number in series: 26-28
Volume: 411
Issue: 26-28
First page : 2559
Last page: 2571
Number of pages: 13
ISSN: 0304-3975
DOI: https://doi.org/10.1016/j.tcs.2010.03.015
Abstract
It is shown that every conjunctive language is generated by a conjunctive grammar from a special subclass, in which every nonterminal A has at most one rule of the general form A -> alpha(1)& ... &alpha(n), while the rest of the rules for A must be of the type A -> w, where w is a terminal string. For context-free grammars, a similar property does not hold (S.A. Greibach et al. (1992)[3]). If it is furthermore required that each rule A -> w has a nonempty w, then a substantial subfamily of conjunctive languages can be generated, yet it remains unknown whether such grammars are as powerful as conjunctive grammars of the general form. (C) 2010 Elsevier B.V. All rights reserved.
It is shown that every conjunctive language is generated by a conjunctive grammar from a special subclass, in which every nonterminal A has at most one rule of the general form A -> alpha(1)& ... &alpha(n), while the rest of the rules for A must be of the type A -> w, where w is a terminal string. For context-free grammars, a similar property does not hold (S.A. Greibach et al. (1992)[3]). If it is furthermore required that each rule A -> w has a nonempty w, then a substantial subfamily of conjunctive languages can be generated, yet it remains unknown whether such grammars are as powerful as conjunctive grammars of the general form. (C) 2010 Elsevier B.V. All rights reserved.
UTU Research Portal