Extended Watson-Crick L systems with regular trigger languages

Abstract

Watson-Crick Lindenmayer systems (L systems) add a control mechanism to ordinary L system derivations. The mechanism is inspired by the complementarity relation in DNA strings, and it is formally defined in terms of a trigger language (trigger, for short). In this paper we prove that Uni-Transitional Watson-Crick E0L systems with regular triggers can recognize the recursively enumerable (RE) languages. We also find that even if the trigger is nondeterministically applied and the number of its applications can be unbounded then the computational power does not change. In the case where the number of applications of the trigger is bounded we find that the computational power lies within the ET0L languages. We also find that Watson-Crick ET0L systems where the number of complementary transitions is bounded by any natural number are equivalent in expressive power. © 2011 Springer-Verlag Berlin Heidelberg.