This
book constitutes the refereed proceedings of the 9th International
Workshop on Reachability Problems, RP 2015, held in Warsaw, Poland, in
September 2015. The 14 papers presented together with 6 extended
abstracts in this volume were carefully reviewed and selected from 23
submissions. The papers cover a range of topics in
the field of reachability for infinite state systems; rewriting systems;
reachability analysis in counter/timed/cellular/communicating automata;
Petri nets; computational aspects of semigroups, groups, and rings;
reachability in dynamical and hybrid systems;
frontiers between decidable and undecidable reachability problems;
complexity and decidability aspects; predictability in iterative maps
and new computational paradigms.