Publication Details
On Tree-Restricted Regular-Controlled Context-Free Grammars
Meduna Alexander, prof. RNDr., CSc. (DIFS FIT BUT)
Soukup Ondřej, Ing. (DIFS FIT BUT)
regular-controlled context-free grammars, restricted derivation trees, contextfreeness of finite index
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.
@ARTICLE{FITPUB11533,
author = "Erzs\'{e}bet Csuhaj-Varj\'{u} and Alexander Meduna and Ond\v{r}ej Soukup",
title = "On Tree-Restricted Regular-Controlled Context-Free Grammars",
pages = "147--163",
journal = "International Journal of Computer Mathematics: Computer Systems Theory",
volume = 2,
number = 4,
year = 2017,
ISSN = "2379-9927",
doi = "10.1080/23799927.2017.1388291",
language = "english",
url = "https://www.fit.vut.cz/research/publication/11533"
}