A bijection is a function f : X -> Y which maps the domain X to the range Y the function f is: # injective (or one-to-one), that is, for every y in Y there is at most one x in X such that f(x) = y, and # surjective (or onto), that is, for every y in Y there is at least one x in X such that f(x) = y. |
A bijection or one-to-one function or one-to-one mapping is a function f : X -> Y which maps the domain X to the range Y such that for every y in Y there is exactly one x in X such that f(x) = y. |