relation: http://eprints.imtlucca.it/180/ title: Constraints for Service Contracts creator: Buscemi, Maria Grazia creator: Coppo, Mario creator: Dezani-Ciancaglini, Mariangiola creator: Montanari, Ugo subject: QA75 Electronic computers. Computer science description: This paper focuses on client-service interactions distinguishing between three phases: negotiate, commit and execute. The participants negotiate their behaviours, and if an agreement is reached they commit and start an execution which is guaranteed to respect the interaction scheme agreed upon. These ideas are materialised through a calculus of contracts enriched with semiring-based constraints, which allow clients to choose services and to interact with them in a safe way. A concrete representation of these constraints with logic programs and logic program combinations is straightforward, thus reducing constraint solution (and consequently the establishment of a contract) to the execution of a logic program. publisher: Università di Pisa, Dipartimento di Informatica date: 2011-03-05 type: Working Paper type: NonPeerReviewed identifier: Buscemi, Maria Grazia and Coppo, Mario and Dezani-Ciancaglini, Mariangiola and Montanari, Ugo Constraints for Service Contracts. Technical Report # /2011 Università di Pisa, Dipartimento di Informatica relation: http://compass2.di.unipi.it/TR/Files/TR-11-05.pdf.gz relation: Technical report TR-11-05