Surjection

1 definition found

From The Free On-line Dictionary of Computing (27 SEP 03) [foldoc]:

  surjection
       
           A function f : A -> B is surjective or onto or a
          surjection if f A = B.  I.e. f can return any value in B.
          This means that its {image} is its {codomain}.
       


          Only surjections have {right inverses}, f' : B -> A where
          f (f' x) = x since if f were not a surjection there would be
          elements of B for which f' was not defined.
       
          See also {bijection}, {injection}.
       
          (1995-05-27)