The requirement is that they are sortable, nothing about the numbers reflecting the actual order of proposals (inasmuch as uncommitted actions in a distributed

The requirement is that they are sortable, nothing about the numbers reflecting the actual order of proposals (inasmuch as uncommitted actions in a distributed system can be considered to be ordered). Concatenating system time and node number upholds this property: 4:01-A and 4:01-B produced by nodes A and B respectively are distinct and numerically sortable, and both in turn "predate" 4:13-C attempted later.