Upcoming paper (to be presented at PLACES 2012, Tallin, 31 Mar 2012)
An event-based model for contracts
M. Bartoletti, T. Cimoli, G.M. Pinna and R. Zunino
Abstract. We introduce an event-based model for contracts. Our model extends event structures with a new relation, which faithfully captures the circular dependencies among contract clauses. We establish whether an agreement exists which respects all the contracts at hand (i.e. all the dependencies can be resolved), and we detect the obligations of each participant.
The main technical contribution is a correspondence between our model and a fragment of the contract logic PCL [Bartoletti&Zunino 2011]. More precisely, we show that the reachable events are exactly those which correspond to provable atoms in the logic. Despite of this strong correspondence, our model improves [Bartoletti&Zunino 2011] by exhibiting a finer-grained notion of culpability, which takes into account the legitimate orderings of events.