Common use of Proof of agreement Clause in Contracts

Proof of agreement. We divide the execution in epochs as follows. Epoch ei is an interval that starts with the first write (according to the linearization σ) to register T [i] and ends immediately before the first write (if any) performed to register T [i + 1]. Given a read, or write, operation op, we say that op occurs in epoch ei, or equivalently, that op is performed in ei, if op is linearized in the interval ei. Clearly, if a write to T [j] occurs in ei, then j ≤ i. The next lemma directly follows from the code of Janus (lines 5 and 7).

Proof of agreement. We divide the execution in epochs as follows. Epoch ei is an interval that starts with the first write (according to the linearization σ) to register T [i] and ends immediately before the first write (if any) performed to register T [i + 1]. Given a read, or write, operation op, we say that op occurs in epoch ei, or equivalently, that op is performed in ei, if op is linearized in the interval ei. Clearly, if a write to T [j] occurs in ei, then j ≤ i. The next lemma directly follows from the code of Janus (lines 5 and 7).