Matrix Equations and Normal Forms for Context-Free Grammars
- 1 July 1967
- journal article
- Published by Association for Computing Machinery (ACM) in Journal of the ACM
- Vol. 14 (3) , 501-507
- https://doi.org/10.1145/321406.321412
Abstract
The relationship between the set of productions of a context-free grammar and the corresponding set of defining equations is first pointed out. The closure operation on a matrix of strings is defined and this concept is used to formalize the solution to a set of linear equations. A procedure is then given for rewriting a context-free grammar in Greibach normal form, where the replacements string of each production begins with a terminal symbol. An additional procedure is given for rewriting the grammar so that each replacement string both begins and ends with a terminal symbol. Neither procedure requires the evaluation of regular begins and ends with a terminal symbol. Neither procedure requires the evaluation of regular expressions over the total vocabulary of the grammar, as is required by Greibach's procedure.Keywords
This publication has 2 references indexed in Scilit:
- A New Normal-Form Theorem for Context-Free Phrase Structure GrammarsJournal of the ACM, 1965
- Two Families of Languages Related to ALGOLJournal of the ACM, 1962