Common use of Alternative Monitoring Semantics Clause in Contracts

Alternative Monitoring Semantics. p q q Proposition 6.1. Let ›→ be the relation defined by the rules in Tables 2 and 3 except that [R15] is replaced by [R21]. If P is a user process and P ›→∗⊃ blame p, then P →∗⊃ blame p. In fact we conjecture that the converse of Proposition 6.1 also holds, namely that single-sided and double-sided monitoring yield the same blames. Proving this fact turns out not to be trivial as the exact relationship between processes resulting from the two monitoring semantics is hard to formalize. As it stands, Proposition 6.1 is enough to conclude that single-sided monitoring does not affect the blame soundness result (Theorem 5.8). We now turn the attention to the rules [R17–R20], which are defined in such a way that a single reduction step rearranges a whole stack of monitors. This formulation of the operational semantics