Symbolic Execution of Acyclic Workflow Graphs

We propose a new technique to analyze the control-flow, i.e., the workflow graph of a business process model, which we call symbolic execution. We consider acyclic workflow graphs that may contain inclusive OR gateways and define a symbolic execution for them that runs in quadratic time. The result allows us to decide in quadratic time, for any pair of control-flow edges or tasks of the workflow graph, whether they are sometimes, never, or always reached concurrently. This has different applications in finding controland data-flow errors. In particular, we show how to decide soundness of an acyclic workflow graph with inclusive OR gateways in quadratic time. Moreover, we show that symbolic execution provides diagnostic information that allows the user to efficiently deal with spurious errors that arise due to over-approximation of the data-based decisions in the process.