Refactoring Problem of Acyclic Extended Free-Choice Workflow Nets to Acyclic Well-Structured Workflow Nets

Abstract

A workflow net (WF-net for short) is a Petri net which represents a workflow. There are two important subclasses of WF-nets: extended free-choice (EFC for short) and well-structured (WS for short). It is known that most actual workflows can be modeled as EFC WF-nets; Acyclic WS is a subclass of acyclic EFC but has more analysis methods. An acyclic EFC WF-net may be transformed to an acyclic WS WF-net without changing the external behavior of the net. We name such a transformation Acyclic EFC WF-net refactoring. We give a formal definition of acyclic EFC WF-net refactoring problem. We also give a necessary condition and a sufficient condition for solving the problem. Those conditions can be checked in polynomial time. These result in the enhancement of the analysis power of acyclic EFC WF-nets.