Asymptotic Notations and Basic Efficiency Classes

Informally, O(g(n)) is the set of all functions with a lower or same order of growth as g(n) (to within a constant multiple, as n goes to infinity). For example;

Ω(g(n)), stands for the set of all functions with a higher or same order of growth as g(n)(to within a constant multiple, as n goes to infinity). For example;

θ(g(n)) is the set of all functions that have the same order of growth as g(n) (to within a constant multiple, as n goes to infinity). For example; every quadratic equation;