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MEDUNA, A. ZEMEK, P.
Originální název
Left Random Context ET0L Grammars
Typ
článek v časopise - ostatní, Jost
Jazyk
angličtina
Originální abstrakt
Consider ET0L grammars. Modify them such that a set of permitting symbols and a set of forbidding symbols are attached to each of their rules, just like in random context grammars. A rule like this can rewrite a symbol if each of its permitting symbols occurs to the left of the symbol to be rewritten in the current sentential form while each of its forbidding symbols does not occur there. ET0L grammars modified in this way are referred to as left random context ET0L grammars, and they represent the principal subject of the investigation in this paper. We prove that these grammars characterize the family of recursively enumerable languages, and without erasing rules, they characterize the family of context-sensitive languages. We also introduce a variety of special cases of these grammars and establish their generative power. In the conclusion, we put all the achieved results into the context of formal language theory as a whole and formulate several open questions.
Klíčová slova
Regulated rewriting; ET0L grammars; random context; left variants; generative power; language families
Autoři
MEDUNA, A.; ZEMEK, P.
Rok RIV
2013
Vydáno
1. 5. 2013
ISSN
0169-2968
Periodikum
Fundamenta Informaticae
Ročník
123
Číslo
3
Stát
Polská republika
Strany od
289
Strany do
304
Strany počet
16
URL
http://iospress.metapress.com/content/b3h6456215g6754p/?p=e7359885e380461c96f9663f43ae8b09&pi=2
BibTex
@article{BUT103402, author="Alexandr {Meduna} and Petr {Zemek}", title="Left Random Context ET0L Grammars", journal="Fundamenta Informaticae", year="2013", volume="123", number="3", pages="289--304", doi="10.3233/FI-2013-811", issn="0169-2968", url="http://iospress.metapress.com/content/b3h6456215g6754p/?p=e7359885e380461c96f9663f43ae8b09&pi=2" }