Expressing and Verifying Business Contracts with Abductive Logic Programming

In this article, we propose to adopt the SCIFF language to specify business contracts and show how its proof procedure is useful to verify contract execution and fulfilment. SCIFF is a declarative language based on abductive logic programming, which accommodates forward rules, predicate definitions, and constraints over finite domain variables. Its declarative semantics is abductive, and can be related to that of deontic operators; its operational specification is a sound and complete proof procedure, defined as a set of transition rules, which has been implemented and integrated into a reasoning and verification tool. A variation of the SCIFF proof-procedure (g-SCIFF) can be used for static verification of contract properties. We demonstrate the use of the SCIFF language for business contract specification and verification, in a concrete scenario. In order to accommodate integration of SCIFF with architectures for business contract, we also show the encoding of SCIFF contract rules in RuleML.