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Parallel Processing Letters, 2016
Coverability trees offer a finite characterization of all the derivations of a context-free parallel grammar system (CF-PCGS). Their finite nature implies that they necessarily omit some information about these derivations. We demonstrate that the omitted information is most if not all of the time too much, and so coverability trees are not useful as ...
Stefan D. Bruda, Mary Sarah Ruth Wilkin
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Coverability trees offer a finite characterization of all the derivations of a context-free parallel grammar system (CF-PCGS). Their finite nature implies that they necessarily omit some information about these derivations. We demonstrate that the omitted information is most if not all of the time too much, and so coverability trees are not useful as ...
Stefan D. Bruda, Mary Sarah Ruth Wilkin
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Non-centralized parallel communicating grammar systems
Bull. EATCS, 2020Summary: The main aim of this note is to introduce to the reader a subject which seems to deserve some attention: the parallel communicating grammar systems (defined in \textit{Gh. Pǎun} and \textit{L. Sâuteau} [An. Univ. Bucar., Mat. 38(2), 55-63 (1989)] as a grammatical model of parallel commuting).
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ON CENTRALIZED PARALLEL COMMUNICATING GRAMMAR SYSTEMS WITH CONTEXT-SENSITIVE COMPONENTS
International Journal of Foundations of Computer Science, 2013Centralized parallel communicating grammar systems with context-sensitive components that work in returning mode can only generate context-sensitive languages. Here we show that, when working in nonreturning mode, these grammar systems generate all languages from the nondeterministic time complexity class NEXT = ∪c ≥ 1 NTIME (2c·n).
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On the syntactic complexity of parallel communicating grammar systems
Kybernetika, 1992Summary: We compare the complexity of generating a language by a context-free grammar or by a parallel communicating grammar system (PCGS), in the sense of Gruska's measures Var, Prod, Symb. Then we define a specific measure of PCGS, Com, dealing with the number of communication symbols appearing in a derivation.
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On the Number of Components and Clusters of Non-returning Parallel Communicating Grammar Systems
2011In 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 ...
Erzsébet Csuhaj-Varjú, György Vaszil
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2013
The paper brings new insights into the complexity of Szilard languages (SZLs) of Parallel Communicating Grammar Systems (PCGSs). We investigate the structure of Szilard words for several classes of PCGSs with context-free rules. We prove that the classes of SZLs of returning centralized and non-returning non-centralized PCGSs are included in circuit ...
Liliana Cojocaru, Erkki Mäkinen
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The paper brings new insights into the complexity of Szilard languages (SZLs) of Parallel Communicating Grammar Systems (PCGSs). We investigate the structure of Szilard words for several classes of PCGSs with context-free rules. We prove that the classes of SZLs of returning centralized and non-returning non-centralized PCGSs are included in circuit ...
Liliana Cojocaru, Erkki Mäkinen
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Parallel Communicating Grammar Systems with Bounded Resources: Results, Techniques, Open Problems
J. Autom. Lang. Comb., 2000Journal of Automata, Languages and Combinatorics, Volume 5, Number 3, 2000, 175 ...
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On the computational complexity of context-free Parallel Communicating Grammar Systems
1997In this paper we investigate the computational complexity for Parallel Communicating Grammar Systems (PCGSs) whose components are context-free grammars. We show that languages generated by nonreturning context-free PCGSs can be recognized by O(n) space-bounded Turing machines.
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ON A VARIANT OF PARALLEL COMMUNICATING GRAMMAR SYSTEMS WITH COMMUNICATION BY COMMAND
2006Erzsébet Csuhaj-Varjú, György Vaszil
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