P. Bonizzoni, G. Mauri, C. Ferretti, R. Zizza
Separating some splicing models.

Abstract

This work shows that the family of languages generated by splicing as defined in the early paper by T.Head is strictly included in the family defined by later definitions by Head, Gh.Paun, and others. It also proves the strict inclusion of this latter family in the splicing family defined by D.Pixton when proving the regularity of splicing languages. We describe instance languages in the difference sets, and prove how they cannot be generated by the smaller families.