Fundamentals of control flow in workflows

Abstract. Although workflow management emerged as a research area well over a decade ago, little consensus has been reached as to what should be essential ingredients of a workflow specification language. As a result, the market is flooded with workflow management systems, based on different paradigms and using a large variety of concepts. The goal of this paper is to establish a formal foundation for control-flow aspects of workflow specification languages, that assists in understanding fundamental properties of such languages, in particular their expressive power. Workflow languages can be fully characterized in terms of the evaluation strategy they use, the concepts they support, and the syntactic restrictions they impose. A number of results pertaining to this classification will be proven. This should not only aid those developing workflow specifications in practice, but also those developing new workflow engines. Received 16 January 2001 / 13 November 2002 This research is supported by an ARC SPIRT grant “Component System Architecture for an Open Distributed Enterprise Management System with Configurable Workflow Support” between QUT and Mincom.