On the Power of Membrane Computing

We continue the investigation of the power of the computability models introduced in [12] under the name of transition super-cell systems. We compare these systems with classic mechanisms in formal language theory, context-free and matrix grammars, E0L and ET0L systems, interpreted as generating mechanisms of number relations (we take the Parikh image of the usual language generated by these mecha- nisms rather than the language). Several open problems are also formulated