karlseguin/the-little-redis-book — pull request #4 by encukou (2012-01-23 20:13:17+00:00)
Title: Make the Big O notation wording correct from a theoretical point of view...

Good job making Big O approachable! Let's also make the wording (more) theoretically sound.

Big O deals with the worst case (upper bound); cf. http://en.wikipedia.org/wiki/Big_O_notation .
And of course you're only using one notation to express the different kinds of behavior.