diff --git a/Data/Exists/Constrained.hs b/Data/Exists/Constrained.hs
--- a/Data/Exists/Constrained.hs
+++ b/Data/Exists/Constrained.hs
@@ -6,5 +6,8 @@
 -- | Dependent sum
 data E c a = ∀ k . (Typeable k, c k) => E { unE :: a k }
 
-liftE :: (∀ k . c k => a k -> b k) -> E c a -> E c b
-liftE f (E a) = E (f a)
+map :: (∀ k . c k => a k -> b k) -> E c a -> E c b
+map f (E a) = E (f a)
+
+mapF :: Functor f => (∀ k . c k => a k -> f (b k)) -> E c a -> f (E c b)
+mapF f (E a) = E <$> f a
diff --git a/exist.cabal b/exist.cabal
--- a/exist.cabal
+++ b/exist.cabal
@@ -1,5 +1,5 @@
 name:                exist
-version:             0.1.1.0
+version:             0.2.0.0
 synopsis:            Dependent sum type
 -- description:
 license:             BSD3