Semi-discrete context-free languages†
Michel Latteux, G. Thierrin · International Journal of Computer Mathematics · 1983
A language L over a finite alphabet is said to be semi-discrete if there exists a positive integer k such that L contains at most k words of any given length. If k=1, the language is said to be discrete. It is shown that a language is semi-discrete and context-free iff it is a discrete union of languages of the form , iff it is a finite disjoint union of discrete context-free languages. Closure properties and decision problems are studied for the class of semi-discrete context-free languages