The unfolding of general Petri nets

Abstract

The unfolding of (1-)safe Petri nets to occurrence nets is well
  understood.  There is a universal characterization of the unfolding
  of a safe net which is part and parcel of a coreflection from the
  category of occurrence nets to the category of safe nets.  The
  unfolding of general Petri nets, nets with multiplicities on arcs
  whose markings are multisets of places, does not possess a directly
  analogous universal characterization, essentially because there is
  an implicit symmetry in the multiplicities of general nets, and that
  symmetry is not expressed in their traditional occurrence net
  unfoldings.  In the present paper, we show how to recover a
  universal characterization by representing the symmetry in the
  behaviour of the occurrence net unfoldings of general Petri nets. We
  show that this is part of a coreflection between enriched categories
  of general Petri nets with symmetry and occurrence nets with
  symmetry.