Computational efficiency and universality of timed P systems with membrane creation

P systems are a class of distributed parallel computing models inspired by the structure and the functioning of a living cell, where the execution of each rule is completed in exactly one time unit (a global clock is assumed). However, in living cells, the execution time of different biological processes is difficult to know precisely and very sensitive to environmental factors that might be hard to control. Inspired from this biological motivation, in this work, timed polarization P systems with membrane creation are introduced and their computational efficiency and universality are investigated. Specifically, we give a time-free semi-uniform solution to the SAT problem by a family of P systems with membrane creation in the sense that the correctness of the solution is irrelevant to the times associated with the involved rules. We also prove that time-free P systems with membrane creation are computationally universal.