one-to-one
or one-one (1-1), adj. 1. (of two sets of individuals) having elements that are able to be paired with one another without remainder, equinumerous. For example, the natural numbers n correspond one-to-one with the points (n, n) on the real plane. 2. also called bijective or into and onto.
(of a mapping) associating a unique member of the codomain with every member of the domain of a function, or a unique first argument with each second argument of a binary relation, and vice versa, as
A one-to-one correspondence between S and T.
For example, there is a 1-1 correspondence between the members of a rugby team and the natural numbers 1 to 15; x → 2x is a 1-1 mapping from the integers to the even integers. These terms are often reserved for the case when the codomain and range coincide. Compare surjective, injective.
For example, there is a 1-1 correspondence between the members of a rugby team and the natural numbers 1 to 15; x → 2x is a 1-1 mapping from the integers to the even integers. These terms are often reserved for the case when the codomain and range coincide. Compare surjective, injective.