Formal languages
String-rewriting systems
On the regularity of languages on a binary alphabet generated by copying systems
Information Processing Letters
Term rewriting and all that
Acta Cybernetica
Some properties of duplication grammars
Acta Cybernetica
Introduction to Formal Language Theory
Introduction to Formal Language Theory
Semigroups Satisfying xm+n = xn
CTRS '92 Proceedings of the Third International Workshop on Conditional Term Rewriting Systems
Algebraic Theory of Automata & Languages
Algebraic Theory of Automata & Languages
Uniformly bounded duplication languages
Discrete Applied Mathematics
Circular words avoiding patterns
DLT'02 Proceedings of the 6th international conference on Developments in language theory
DNA Computing: New Computing Paradigms
DNA Computing: New Computing Paradigms
On Regularity-Preservation by String-Rewriting Systems
Language and Automata Theory and Applications
| Hi-index | 5.23 |
Duplication languages are generated from an initial word by iterated application of string-rewriting rules of the form u-uu. In several recent articles such languages have been investigated with a main focus on finding their placement in the Chomsky hierarchy. We generalize the generating rules to u^m-u^n with arbitrary m and n. When the length of the factor u is a fixed number, most cases result in regular languages. If there is just some bound on the length, then often non-regular but always context-free languages are generated. The regularity conditions for both variants are fully characterized, and confluence for the underlying rewrite relations is determined. For the unrestricted case only some results are presented which carry over from restricted variants.