On CD-systems of stateless deterministic two-phase RR(1)-automata

Abstract

We study stateless deterministic two-phase RR-automata of window size one: stl-det-2-RR(1)-automata. While general deterministic RR-automata of window size one characterize the regular languages, it turns out that the class of languages accepted by the stateless two-phase variants is subregular. Therefore we combine stl-det-2-RR(1)-automata into computationally stronger cooperating distributed systems, obtaining the stl-det-local-CD-2-RR(1)-systems. By limiting their inherent nondeterminism, two further variants are derived. The relations between the different classes and some well-known language families are investigated, and it is shown that the classes defined here form a finite hierarchy whose levels are incomparable to several well-known language families. Further, closure properties and decision problems are studied for these classes. © 2012 Springer-Verlag Berlin Heidelberg.