Review big-Oh def'n. Show: λn.n ∈ O(2) Show: λn.n ∉ O(n) Related concepts: ω(), Ω(), Θ(), O(), o() >, ≥, =, ≤, < [up to a constant, ignoring small inputs] Binary search. What is the running time? n + 2(n/2) + 4(n/4) + ... + n(1)