The computational power of monodirectional tissue P systems with symport rules

Tissue P systems with symport/antiport rules are parallel bio-inspired devices that evolve by communicating objects between two regions in both directions. In this paper, a type of tissue P systems, called monodirectional tissue P systems with symport rules (MTS P systems) is considered, where communication happens between two regions only in one direction. Results show that MTS P systems are Turing universal with three cells and using a maximal length 2 of symport rules working in a maximally parallel way. Besides, the Turing universality of MTS P systems is also achieved by using two cells, and a maximal length 1 of symport rules working in a synchronized way by imposing a flat maximal parallelism among rules in the set. These results show that with the restrictive condition of "monodirectionality", MTS P systems are still computationally powerful. Therefore, developing membrane algorithms for MTS P systems is potentially exploitable.