Weak Metrics on Configurations of a P System

Abstract

The evolution of a P system generates a tree of computation po- tentially in¯nite where it is very difficult to set the degree of closeness between two configurations. The problem is specially hard if we want to quantify that proximity in order to make useful comparisons. In this paper we propose some weak metrics on configurations of a P system with a fixed structure of mem- branes and briefly discuss their advantages and drawbacks.