Lamport’s paper introduces a new function, essentially a counter, in every process that can assign a number to an event. Let’s call this function as Ci(A) as a counter in process i for event a. There are no physical clocks in the system. The function C(A) establishes the invariant that, event a must have happened before b, then C(A) < C(B). Using this function, a partial ordering of events in the system can be established using the following two conditions: