Not exactly, partial functions can be surjective, eg f :: Int -> Bool f 0 = True f 1 = False f n = f (n + 1) is surjective onto Bool but also partial (does

Not exactly, partial functions can be surjective, eg f :: Int -> Bool f 0 = True f 1 = False f n = f (n + 1) is surjective onto Bool but also partial (doesn't return for n > 1). In Haskell we say that when a function doesn't return, the output is bottom, written as ⊥. You could say that a function f : A -> B is partial if f^{-1}(B \ ⊥) is surjective.