#10 More about Big-Omega

The statement of big-omega is shown below:
∃c ϵ ℝ+ ∃B ϵ ℕ, ∀n ϵ ℕ, n ≥B ⇒ f(n) ≥ cn2 

This is basically the same statement as the big-oh nontaion, except the less than or equal is replaced by bigger than or equal to.

So the cn^2 is the greatest lower bound of the function, it is closest to the running time under best case.

And the proof method is as same as the big-oh, which is using the proof structure.