a function that is both injective and surjective

A bijection is an operation that associates two sets in such a way that each member of the codomain T, is paired with exactly one member of the domain D. A bijection is both injective and surjective and has an inverse.

In mathematics, a function f from a set X to a set Y is said to be bijective if for every y in Y there is exactly one x in X such that f(x) = y.

A one-to-one and onto map.

A one-to-one onto function.