Affiliations: Department of Computer Science and Engineering, Indian Institute of Technology, Madras, Chennai-36, India. kamala@iitm.ac.in | Institute of Mathematics of the Romanian Academy, PO Box 1-764, 014700 Bucureşti, Romania. gpaun@us.es, ghpaun@gmail.com | Department of Computer Science and Engineering, Indian Institute of Technology, Madras, Chennai-36, India. ajeeshramanujan@gmail.com
Note: [] Also work: Department of Computer Science and Artificial Intelligence, University of Sevilla, Avda. Reina Mercedes s/n, 41012 Sevilla, Spain
Abstract: We introduce and briefly investigate P systems with controlled computations. First, P systems with label restricted transitions are considered (in each step, all rules used have either the same label, or, possibly, the empty label, λ), then P systems with the computations controlled by languages (as in context-free controlled grammars). The relationships between the families of sets of numbers computed by the various classes of controlled P systems are investigated, also comparing them with length sets of languages in Chomsky and Lindenmayer hierarchies (characterizations of the length sets of ET0L and of recursively enumerable languages are obtained in this framework). A series of open problems and research topics are formulated.
Keywords: Membrane computing, P system, control word, Chomsky language, Lindenmayer language
