<P> In mathematics , a function f from a set X to a set Y is surjective ( or onto ) , or a surjection , if for every element y in the codomain Y of f there is at least one element x in the domain X of f such that f ( x ) = y . It is not required that x is unique ; the function f may map one or more elements of X to the same element of Y . </P>
<P> In mathematics , a function f from a set X to a set Y is surjective ( or onto ) , or a surjection , if for every element y in the codomain Y of f there is at least one element x in the domain X of f such that f ( x ) = y . It is not required that x is unique ; the function f may map one or more elements of X to the same element of Y . </P>
when is a function said to be onto
when is a function said to be onto
if for every element y in the codomain Y of f there is at least one element x in the domain X of f such that f ( x ) = y
if for every element y in the codomain Y of f there is at least one element x in the domain X of f such that f ( x ) = y