f(n) = O(g(n)) 
iff ∃ positive c, n_{0} such that 0 ≤ f (n) ≤ cg(n) ∀n ≥ n_{0}. 
f(n) = Ω(g(n)) 
iff ∃ positive c, n_{0} such that f (n) ≥ cg(n) ≥ 0 ∀n ≥ n_{0}. 
f(n) = Θ(g(n)) 
iff f(n) = O(g(n)) and f(n) = Ω(g(n)) 
f(n) = o(g(n)) 

iff ∀ε > 0, ∃n_{0} such that ∣ a_{n} − a∣ < ε, ∀n ≥ n_{0}. 

sup S 
least b ∈ ℝ such that b ≥ s, ∀s ∈ S. 
inf S 
greatest b ∈ ℝ such that b ≤ s ∀s ∈ S. 
Combinations: ... 
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