On Reachability and Spatial Reachability in Fragments of BioAmbients

BioAmbients is a powerful model for representing various aspects of living cells. The model provides a rich set of operations for the movement and interaction of molecules. The richness of the language motivates the study of dialects of the full model and the comparison with other computational models. In this paper we investigate the limit between decidability and undecidability of two decision problems, namely reachability and spatial reachability, for semantic and syntactic fragments of BioAmbients providing movement capabilities and merge. Our results illustrate the power of merge with respect to the other movement operations of BA for properties like reachability. Furthermore, they establish an interesting connection between BioAmbients and other computational models like associative-commutative term rewriting and Petri nets with transfer arcs.