A Theoretical Basis for Run-time Monitoring of Contracts

Electronic inter-organizational relationships are governed by contracts regulating their interaction. It is necessary to run-time monitor the contracts, as to guarantee their fulfillment as well as the enforcement of penalties in case of violations. The present work shows how to obtain a run-time monitor for contracts written in CL, a specification language that allows writing conditional obligations, permissions and prohibitions over actions. We first give a trace semantics for CL which formalizes the notion of a trace fulfills a contract. We show how to obtain, for a given contract, a linear-size alternating Büchi automaton accepting exactly the traces which fulfill the contract. This automaton is the basis for obtaining a finite state machine which acts as a run-time monitor for CL contracts.