Tissue-like P Systems Without Environment

In this paper we present a tissue-like P systems model with cell division the environment has been replaced by an extra cell. In such model, we present a uniform family of recognizer P systems which solves the Subset Sum problem. This solution establishes a new frontier for the tractability of computationally hard problems in Membrane Computing, since it proves that NP-complete problems can be solved without an arbitrarily large amount of objects in the environment.