If anyone is interested in hearing what's wrong with that post, please ask and I will explain. Otherwise, I won't waste my time.
That's not a very useful response. If you have an objection to my post - please elaborate since otherwise we can't really discuss it. And that's the point of a forum, to discuss things - isn't it?
Or would you like me to guess why you disagree?
It isn't true that Big-O = worst case, Big-Omega = best case, and Big-Theta = average case.
Big-O = upper bound. We are often interested in an upper bound on the worst case so it gets associated with worst case behavior, but we are also often interested in an upper bound on average case behavior, etc.
Hmm.. You're right - I should have used upper bound, lower bound etc instead of worst case, best case etc.
And on more complex algorithms with very complicated behaviour I can see how we'd want to consider the upper bound on the average behavior etc.
I'm still not entirely convinced that using Big-O in such a manner is the best approach, but at least the way you explained it seems mathematically sound.