diff --git a/src/Data/Cross.hs b/src/Data/Cross.hs
--- a/src/Data/Cross.hs
+++ b/src/Data/Cross.hs
@@ -1,5 +1,6 @@
 {-# LANGUAGE FlexibleInstances, FlexibleContexts, TypeOperators
-           , TypeFamilies, TypeSynonymInstances  #-}
+           , TypeFamilies, TypeSynonymInstances 
+           , UndecidableInstances  #-}
 {-# OPTIONS_GHC -Wall #-}
 ----------------------------------------------------------------------
 -- |
diff --git a/vector-space.cabal b/vector-space.cabal
--- a/vector-space.cabal
+++ b/vector-space.cabal
@@ -1,5 +1,5 @@
 Name:                vector-space
-Version:             0.14
+Version:             0.15
 Cabal-Version:       >= 1.8
 Synopsis:            Vector & affine spaces, linear maps, and derivatives
 Category:            math