A survey of behaviour and equivalence preserving refinements of petri nets

Results on refinements of places and transitions in Petri nets are surveyed. Such refinements may either transform a net to a refined net with the same behaviour, where behaviour often means safeness or liveness. Or they may transform semantically equivalent nets to refined nets which are semantically equivalent again. Here the semantics of a net is a description of the possible runs incorporating information on choices to a varying degree.