Journal articleMASOPUST Tomáš, MEDUNA Alexander and ŠIMÁČEK Jiří. Two PowerDecreasing Derivation Restrictions in Generalized Scattered Context Grammars. Acta Cybernetica. 2008, vol. 18, no. 4, pp. 783793. ISSN 0324721X.  Publication language:  english 

Original title:  Two PowerDecreasing Derivation Restrictions in Generalized Scattered Context Grammars 

Title (cs):  Dvě omezení snižující sílu zobecněných gramatik s rozptýleným kontextem 

Pages:  783793 

Book:  Acta Cybernetica 

Place:  Szeged, HU 

Year:  2008 

Journal:  Acta Cybernetica, Vol. 18, No. 4, US 

ISSN:  0324721X 

URL:  http://www.inf.uszeged.hu/actacybernetica/edb/vol18n4/Masopust_2008_ActaCybernetica.xml [HTML] 

Keywords 

scattered context grammar, grammatical generalization, derivation restriction, generative power. 
Annotation 

The present paper introduces and discusses generalized scattered context grammars that are based upon sequences of productions whose lefthand sides are formed by nonterminal strings, not just single nonterminals. It places two restrictions on the derivations in these grammars. More specifically, let k be a positive integer. The first restriction requires that all rewritten symbols occur within the first k symbols of the first continuous block of nonterminals in the sentential form during every derivation step. The other restriction defines derivations over sentential forms containing no more than k occurrences of nonterminals. As its main result, the paper demonstrates that both restrictions decrease the generative power of these grammars to the power of contextfree grammars. 
BibTeX: 

@ARTICLE{
author = {Tom{\'{a}}{\v{s}} Masopust and Alexander Meduna and
Ji{\v{r}}{\'{i}} {\v{S}}im{\'{a}}{\v{c}}ek},
title = {Two PowerDecreasing Derivation Restrictions in Generalized
Scattered Context Grammars},
pages = {783793},
booktitle = {Acta Cybernetica},
journal = {Acta Cybernetica},
volume = {18},
number = {4},
year = {2008},
location = {Szeged, HU},
ISSN = {0324721X},
language = {english},
url = {http://www.fit.vutbr.cz/research/view_pub.php?id=8546}
} 
