Closure properties of selective substitution grammars part I
Jakob Gonczarowski, H. C. M. Kleijn, Grzegorz Rozenberg · International Journal of Computer Mathematics · 1983
Let be the class of languages generated by selective substitution grammars, where: 1) arbitrary productions of the form are allowed, where b is a letter and w is a word and 2) the selectors used are from . This is the first part of a paper consisting of two parts that investigates how various language-theoretical properties of influence the closure properties of In this part basic techniques for manipulating selectors of selective substitution grammars are established. Then we investigate how properties of influence the closure of under union and concatenation.