@article {835,
	title = {P automata revised},
	journal = {Theoretical Computer Science},
	year = {2012},
	publisher = {Elsevier},
	address = {Amsterdam (The Netherlands)},
	abstract = {We continue here the investigation of P automata, in their non-extended case, a class of devices which characterize non-universal family of languages. First, a recent conjecture is confirmed: any recursively enumerable language is obtained from a language recognized by a P automaton, to which an initial (arbitrarily large) string is added. Then, we discuss possibilities of extending P automata, following suggestions from string finite automata. For instance, automata with a memory (corresponding to push-down automata) are considered and their power is briefly investigated, as well as some closure properties of the family of languages recognized by P automata. In the context, a brief survey of results about P and dP automata (a distributed version of P automata) is provided, and several further research topics are formulated.},
	keywords = {Membrane computing; P automata; Turing computability; Closure properties},
	issn = {0304-3975},
	doi = {10.1016/j.tcs.2012.01.036},
	url = {http://www.sciencedirect.com/science/article/pii/S0304397512000837?v=s5},
	author = {Gheorghe Paun and Mario J. P{\'e}rez-Jim{\'e}nez}
}
