Summary. It is well known that the polynomial complexity class of recognizer polarizationless P systems with active membranes, without dissolution and with division for elementary and non-elementary membranes is exactly the complexity class P (see [6], Th. 2). In this paper, we prove that if such P system model is endowed with antimatter and annihilation rules, then NP problems can be solved. In this way, antimatter is a frontier of tractability in Membrane Computing.
