We consider membrane systems where the generation/transformation of objects can take place only if it is linked to communication rules. More specifically, all the rules move objects through membranes and, moreover, the membranes can modify the objects as they pass through. The intuitive interpretation of such rules is that a multiset of objects can move from a region to an adjacent one, and moreover objects can engage into (biochemical) reactions while passing through (are in "contact" with) a membrane. Therefore such "twofold" rules are called symport-rewriting (in short, sr) rules, where symport refers to a coordinated passage of a "team" of molecules through a membrane. In this paper we investigate the influence of the form of sr rules on the power of membrane systems that employ them (sometime in combination with simple antiport rules which allow a synchronized exchange, through a membrane, of two molecules residing in two adjacent regions). A typical restriction on the form of an sr rule requires that the passage described by the rule is such that the sort of exiting molecules is a subset of the sort of entering molecules (however the multiplicities of sorts do not have to be related). We also compare the sequential passage mode with the maximally parallel passage mode.
|Number of pages||21|
|Journal||Journal of Automata, Languages and Combinatorics|
|Publication status||Published - 2006|