“…The idea to attack computationally hard problems by means of P systems has been introduced quite early in the area of Membrane Computing, by considering the idea of active membranes [28]: new membranes are generated from existing ones through membrane division (mimicking the mitosis process), and then used in parallel to solve problems in or even in . Allowing or forbidding the use of some features, or considering different organizations of the membranes, results in systems of a different computational efficiency (see, e.g., [5,8,9,16,24,34,39,41,45,46]). Anyhow, this is not always the case: the use of some features can be considered (like, e.g.…”