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MEDUNA, A. ZEMEK, P.
Original Title
One-Sided Random Context Grammars
Type
journal article - other
Language
English
Original Abstract
The notion of a one-sided random context grammar is defined as a context-free-based regulated grammar, in which a set of permitting symbols and a set of forbidding symbols are attached to every rule, and its set of rules is divided into the set of left random context rules and the set of right random context rules. A left random context rule can rewrite a nonterminal if each of its permitting symbols occurs to the left of the rewritten symbol in the current sentential form while each of its forbidding symbols does not occur there. A right random context rule is applied analogically except that the symbols are examined to the right of the rewritten symbol. The paper demonstrates that without erasing rules, one-sided random context grammars characterize the family of context-sensitive languages, and with erasing rules, these grammars characterize the family of recursively enumerable languages. In fact, these characterization results hold even if the set of left random context rules coincides with the set of right random context rules. Several special cases of these grammars are considered, and their generative power is established. In its conclusion, some important open problems are suggested to study in the future.
Keywords
Regulated rewriting, random context grammars, one-sided variants, generative power, language families
Authors
MEDUNA, A.; ZEMEK, P.
RIV year
2011
Released
21. 4. 2011
ISBN
0001-5903
Periodical
Acta Informatica
Year of study
48
Number
3
State
Federal Republic of Germany
Pages from
149
Pages to
163
Pages count
15
URL
http://www.springerlink.com/content/c70163w7764u8660/
BibTex
@article{BUT49880, author="Alexandr {Meduna} and Petr {Zemek}", title="One-Sided Random Context Grammars", journal="Acta Informatica", year="2011", volume="48", number="3", pages="149--163", doi="10.1007/s00236-011-0134-y", issn="0001-5903", url="http://www.springerlink.com/content/c70163w7764u8660/" }