Acta Informatica
Teams in grammar systems: hybridity and weak rewriting
Acta Cybernetica - Special issue: selected papers of the workshop grammar systems: recent results and perspectives, Budapest, July 1996
Handbook of formal languages, vol. 2
Grammar Systems: A Grammatical Approach to Distribution and Cooperation
Grammar Systems: A Grammatical Approach to Distribution and Cooperation
Teams in Grammar Systems: Sub-Context-Free Cases
New Trends in Formal Languages - Control, Cooperation, and Combinatorics (to Jürgen Dassow on the occasion of his 50th birthday)
PC grammar systems with five context-free components generate all recursively enumerable languages
Theoretical Computer Science
Computation: finite and infinite machines
Computation: finite and infinite machines
Dynamical Teams in Eco-Grammar Systems
Fundamenta Informaticae
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In this paper, we study the size complexity of nonreturning parallel communicating grammar systems. First we consider the problem of determining the minimal number of components necessary to generate all recursively enumerable languages. We present a construction which improves the currently known best bounds of seven (with three predefined clusters) and six (in the non-clustered case) to five, in both cases (having four clusters in the clustered variant). We also show that in the case of unary languages four components are sufficient. Then, by defining systems with dynamical clusters, we investigate the minimal number of different query symbols necessary to obtain computational completeness. We prove that for this purpose three dynamical clusters (which means two different query symbols) are sufficient in general, which (although the number of components is higher) can also be interpreted as an improvement in the number of necessary clusters when compared to the case of predefined clusters.