Affiliations: Department of Computer Science & Engineering,
Indian Institute of Technology, Bombay, Powai, Mumbai-76, India.
krishnas@cse.iitb.ac.in | Department of Mathematics, Indian Institute of
Technology, Madras, Chennai-36, India. ramar@iitm.ac.in;
ramesh_h@iitm.ac.in
Note: [] Address for correspondence: Department of Computer Science and
Engineering, Indian Institute of Technology, Powai, Mumbai-76, India
Abstract: In this paper, we continue the study of contextual and rewriting P
systems. In contextual P systems, we improve a universality result avoiding the
extended feature and by using rules of small weight. In rewriting P systems, we
have two (rather surprising) universality results, both of them using three
membranes, for non-extended systems with replicated rewriting and with leftmost
rewriting, respectively.
Keywords: P systems, contextual grammars, replicated rewriting, leftmost rewriting, recursively enumerable languages
