  Reaction systems are discrete dynamical systems inspired by bio-chemical
processes, whose dynamical behaviour is expressed by set-theoretic operations
on finite sets. Reaction systems thus provide a description of bio-chemical
phenomena that complements the more traditional approaches, for instance those
based on differential equations. A comprehensive list of decision problems
about the dynamical behavior of reaction systems (such as cycles and
fixed/periodic points, attractors, and reachability) is provided along with the
corresponding computational complexity, which ranges from tractable problems to
PSPACE-complete problems.
