This looks like what is described in Section 4 to me: http://www.haskell.org/haskellwiki/Applicative_functor#Applicative_transfomers - jeremy On Oct 12, 2009, at 11:22 AM, Kim-Ee Yeoh wrote: > <**> :: (Applicative m, Applicative n) => > m (n (a->b)) -> m (n a) -> m (n b)