Calculi for Service Oriented Computing

It is widely recognised that process calculi stay to concurrent computing as lambda-calculus stays to sequential computing; in fact, they lay abstract, rigorous foundations for the analysis of interactive, communicating systems. Nowadays, the increasing popularity of Service-Oriented Computing (SOC) challenges the quest for novel abstractions tailored to the well-disciplined handling of specific issues, like long running interactions, orchestration, and unexpected events. In fact, these features emerge neatly in most SOC applications and need to be studied as first-class aspects, whereas they would be obfuscated if dealt with by sophisticated encoding in traditional process calculi. This paper overviews some of the most recent proposals emerged in the literature, pointing out their main characteristics and presents in more detail one such proposal, called caspis, by providing several examples to give evidence of its flexibility. No prior acquaintance with process calculi is assumed, indeed a gentle introduction to their basics is provided before the more advanced material be presented.