We present a classification of slender 0L languages into four classes and give decision methods for two of the classes. Open problems are mentioned, ...

We show that if a 0L language L over a two-letter alphabet is slender then L is a D0L language or L is a bounded language. As an application we prove the ...

If an unbounded letter of a slender 0L system is nondeterministic, then the differ- ent descendants derived in the same steps have prime 2-factors. Indeed, the ...

Salomaa have proved that all DOL languages are slender [8]. There are some other subfamilies of OL languages which consist of slender languages only [6, 7, 2].

We show that if a 0L language L over a two-letter alphabet is slender then L is a D0L language or L is a bounded language. As an application we prove the ...

It is shown that if a 0L language over a two-letter alphabet is slender then L is a D0L language or $L$ is a bounded language and the decidability of the ...

A language L is called slender if there exists a constant k such that L contains no k words of equal length. In this paper we continue the study of ...

In this paper we study the question whether or not the union of two OL languages is a OL language. We show that in general this question is undecidable and that ...

... slender languages and bounded languages. We show that if a 0L language L over a two-letter alphabet is slender then L is a D0L language or L is a bounded ...

In this paper we continue the study of relationships between slender languages and bounded languages. We show that if a 0L language L over a two-letter alphabet ...