Two Step Framework to Extend Workflow Nets and Soundizability Problem

We discuss in this paper whether we can extend work-flow nets (WF-nets for short) under the condition to preserve behavioral inheritance and soundness. We propose a two step framework to extend WF-nets, i.e. we first extend a given WF-net under the condition to preserve only behavioral inheritance, and then correct it to be sound if necessary. We tackle a problem of deciding whether we can correct an unsound WF-net to be sound under the condition to preserve behavioral inheritance, named soundizability problem. There are two kinds of behavioral inheritance: Projection inheritance and protocol inheritance. Our results show that if an acyclic free choice WF-net is extended under the condition to preserve projection inheritance, the extended WF-net is sound; If an acyclic free choice WF-net is extended under the condition to preserve protocol inheritance, the extended WF-net may be unsound; The unsound extended WF-net cannot be corrected to be sound under the condition to preserve projection inheritance, but may be corrected under the condition to preserve protocol inheritance.