?url_ver=Z39.88-2004&rft_id=Technical+report+TR-11-05&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Feprints.imtlucca.it%2F180%2F&rft.title=Constraints+for+Service+Contracts%0D%0A&rft.creator=Buscemi%2C+Maria+Grazia&rft.creator=Coppo%2C+Mario&rft.creator=Dezani-Ciancaglini%2C+Mariangiola&rft.creator=Montanari%2C+Ugo&rft.subject=QA75+Electronic+computers.+Computer+science&rft.description=This+paper+focuses+on+client-service+interactions+distinguishing+between+three+phases%3A+negotiate%2C+commit+and+execute.+The+participants+negotiate+their+behaviours%2C+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%2C+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%2C+thus+reducing+constraint+solution+(and+consequently+the+establishment+of+a+contract)+to+the+execution+of+a+logic+program.&rft.publisher=Universit%C3%A0+di+Pisa%2C+Dipartimento+di+Informatica&rft.date=2011-03-05&rft.type=Working+Paper&rft.type=NonPeerReviewed&rft.identifier=++Buscemi%2C+Maria+Grazia+and+Coppo%2C+Mario+and+Dezani-Ciancaglini%2C+Mariangiola+and+Montanari%2C+Ugo++Constraints+for+Service+Contracts.++Technical+Report++%23+%2F2011++++Universit%C3%A0+di+Pisa%2C+Dipartimento+di+Informatica+++++++++&rft.relation=http%3A%2F%2Fcompass2.di.unipi.it%2FTR%2FFiles%2FTR-11-05.pdf.gz&rft.relation=Technical+report+TR-11-05