Publication Details
Phrase-Structure Grammars: Normal Forms and Reduction
formal languages, phrase-structure grammars, normal forms
This paper establishes two new normal forms for phrase-structure grammars in
which both context-free rules and non-context-free rules are in prescribed forms.
In addition, a limit is placed on the number of context-free rules. More
specifically, the first form has 2 + n context-free rules, where n is the number
of terminals. Concerning non-context-free rules, each of them has the form AB ->
CD, where A, B, C, D are nonterminals. The second normal form has always only two
context-free rules---S -> S# and # -> e, where S is the start symbol, # is
a nonterminal, and e is the empty string. Regarding non-context-free rules, each
of them is of the form AB -> XD, where A, B, D are nonterminals and X is
a nonterminal or a terminal.
@article{BUT130900,
author="Zbyněk {Křivka} and Alexandr {Meduna} and Petr {Zemek}",
title="Phrase-Structure Grammars: Normal Forms and Reduction",
journal="COMPUTER JOURNAL",
year="2016",
volume="59",
number="8",
pages="1180--1185",
doi="10.1093/comjnl/bxw001",
issn="0010-4620",
url="https://www.fit.vut.cz/research/publication/9949/"
}