Shape analysis for mobile ambients

The ambient calculus is a calculus of computation that allows active processes to move between sites. We present an analysis inspired by state-of-the-art pointer analyses that safety and accurately predicts which processes may turn up at what sites during the execution of a composite system. The analysis models sets of processes by sets of regular tree grammars enhanced with context-dependent counts, and it obtains its precision by combining a powerful redex materialisation with a strong redex reduction (in the manner of the strong updates performed in pointer analyses). The underlying ideas are flexible and scale up to general tree structures admitting powerful restructuring operations.