P Systems with One Membrane and Symport/Antiport Rules of Five Symbols Are Computationally Complete

We consider P systems with only one membrane using symport/antiport rules and prove that any recursively enumerable set of k-dimensional vectors of natural numbers can be generated (accepted) by using at most k + 4 symbols; hence, any recursively enumerable set of natural numbers can be generated (accepted) by using at most five symbols.