We prove that P systems with mate and drip operations and using at most seven membranes during any step of a computation are universal. This improves a recent similar result, where eleven membranes are used. The proof of this result has the “drawback” that the output of a computation is obtained on an inner membrane of the system. A universality proof is then given for the case when the result of a computation is found on the skin membrane (on its external side, hence “visible” from the environment), but in this case we use one more membrane, as well as another basic brane operation exo; moreover, the operations are now of the projective type, as previously introduced.
Two universality results for (mem)brane systems - TR presso Universidad de Sevilla, Spain
FRANCO, Giuditta;
2006-01-01
Abstract
We prove that P systems with mate and drip operations and using at most seven membranes during any step of a computation are universal. This improves a recent similar result, where eleven membranes are used. The proof of this result has the “drawback” that the output of a computation is obtained on an inner membrane of the system. A universality proof is then given for the case when the result of a computation is found on the skin membrane (on its external side, hence “visible” from the environment), but in this case we use one more membrane, as well as another basic brane operation exo; moreover, the operations are now of the projective type, as previously introduced.
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