Common use of Semantics of Predicates Rules Clause in Contracts

Semantics of Predicates Rules. The second category of rules allows a user to utilize any domain specific predicates within an SLO by defining how two SLOs with that predicate should be compared. A semantics rule should compare SLOs according to the predicate semantics and assert an isStronger or isEquivalent triple into Snobase. The following ARL rule defines the semantics of the predicate “less”. hasSLO(G2, SLO2) and hasExpression (SLO2, E2) and hasPredicate(E2, P2) and hasType(P2, “less”) and hasParameter(E2, p2) and p2 == p1 and hasValue(E2, V2) do: if (V1<V2) assert [E1 isStronger E2] else if (V1>V2) assert [E2 isStronger E2] else assert [E1 isEquivalent E2] The above rule compares the values of SLOs from different agreements with the same predicate and parameter and asserts isEquivalent if the values are the same otherwise it states which expression is stronger based on the semantics of the predicate “less”. This rule can also be further customized by incorporating parameters or checking units to determine whether to do a string or numeric comparison. The benefit of this approach is two-fold. First, it allows for domain predicate flexibility such that we do not restrict which predicates our matcher can compare but rather allow the user to introduce new predicates by defining the semantics with an ARL rule. Second, since rules are fired automatically as the agreements are being loaded into Snobase, the SLOs are compared much before the search process. This simplifies the search algorithm because to find a match for SLO1 we quickly query for all SLOs who have been asserted isStronger than or isEquivalent to SLO1. The semantics of predicate rules have the lowest priority so that the other rules may execute before the final evaluation is performed.