The Omega Rep is the process by which the bar is properly returned to the rack at the end of the set. Sully describes how the proper performance of the Omega rep insures that every set ends with safety, authority, and dignity. All you have to do is remember the four magic words: THERE ARE NO HOOKS.
In many ways, the most important rep of the set is the one you never log--the ZEROTH rep, the one in which the bar is unracked and carried out. The zeroth rep has a big impact on the technical parameters of the remaining reps of the set. Give it the respect it deserves!