Conţinutul numărului revistei |
Articolul precedent |
Articolul urmator |
526 0 |
SM ISO690:2012 ALHAZOV, Artiom, FREUND, Rudolf, IVANOV, Sergiu, PAN, Linqiang, SONG, Bosheng. Time-freeness and clock-freeness and related concepts in P systems. In: Theoretical Computer Science, 2020, nr. 805, pp. 127-143. ISSN 0304-3975. DOI: https://doi.org/10.1016/j.tcs.2018.09.009 |
EXPORT metadate: Google Scholar Crossref CERIF DataCite Dublin Core |
Theoretical Computer Science | ||||||
Numărul 805 / 2020 / ISSN 0304-3975 /ISSNe 1879-2294 | ||||||
|
||||||
DOI:https://doi.org/10.1016/j.tcs.2018.09.009 | ||||||
Pag. 127-143 | ||||||
|
||||||
Rezumat | ||||||
In the majority of models of P systems, rules are applied at the ticks of a global clock and their products are introduced into the system for the following step. In timed P systems, different integer durations are statically assigned to rules; time-free P systems are P systems yielding the same languages independently of these durations. In clock-free P systems, durations are real and are assigned to individual rule applications; thus, different applications of the same rule may last for a different amount of time. In this paper, we formalise timed, time-free, and clock-free P system within a framework for generalised parallel rewriting. We then explore the relationship between these variants of semantics. We show that clock-free P systems cannot efficiently solve intractable problems. Moreover, we consider un-timed systems where we collect the results using arbitrary timing functions as well as un-clocked P systems where we take the union over all possible per-instance rule durations. Finally, we also introduce and study mode-free P systems, whose results do not depend on the choice of a mode within a fixed family of modes, and compare mode-freeness with clock-freeness. |
||||||
Cuvinte-cheie Clock-freeness, Mode-freeness, P system, Time-freeness |
||||||
|