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MEDUNA, A. SOUKUP, O. CSUHAJ-VARJÚ, E.
Original Title
On Tree-Restricted Regular-Controlled Context-Free Grammars
Type
journal article in Scopus
Language
English
Original Abstract
This paper gives simple tree-based conditions under which regular-controlled context-free grammars generate context-free languages of finite index, so they cannot even generate all context-free languages. It defines the notion of path-changing derivation step which corresponds to performing two consecutive rewritings of nonterminal symbols present in the different branches of the derivation tree. It proves that if there exists a certain constant that limits the number of path-changing deriva- tion steps, then, the regular-controlled grammar generates a context-free language of finite index. At the end, we generalize achieved result and provide some open problems for future study.
Keywords
regular-controlled context-free grammars, restricted derivation trees, contextfreeness of finite index
Authors
MEDUNA, A.; SOUKUP, O.; CSUHAJ-VARJÚ, E.
Released
27. 10. 2017
ISBN
2379-9927
Periodical
International Journal of Computer Mathematics: Computer Systems Theory
Year of study
2
Number
4
State
United Kingdom of Great Britain and Northern Ireland
Pages from
147
Pages to
163
Pages count
17
URL
http://dx.doi.org/10.1080/23799927.2017.1388291
BibTex
@article{BUT144477, author="Alexandr {Meduna} and Ondřej {Soukup} and Erzsébet {Csuhaj-Varjú}", title="On Tree-Restricted Regular-Controlled Context-Free Grammars", journal="International Journal of Computer Mathematics: Computer Systems Theory", year="2017", volume="2", number="4", pages="147--163", doi="10.1080/23799927.2017.1388291", issn="2379-9927", url="http://dx.doi.org/10.1080/23799927.2017.1388291" }