However, this article focuses on just those events that are the arrival of a message sent to an Actor.
Arrival ordering is determined by arbitration in processing messages (often making use of a digital circuit called an arbiter).
It is sufficient to show that there is an Actor computation that satisfies the previously stated laws but violates the Law of Finite Chains Between Events in the Combined Ordering.
However, we know from physics that infinite energy cannot be expended along a finite trajectory.
Subsequently Hewitt [2006] augmented the diagrams with arrival times to construct a technically simpler denotational model that is easier to understand.