diff --git a/rings.cabal b/rings.cabal
--- a/rings.cabal
+++ b/rings.cabal
@@ -1,5 +1,5 @@
 name:                rings
-version:             0.0.2.3
+version:             0.0.2.4
 synopsis:            Groups, rings, semirings, and dioids.
 description:         Lawful algebraic classes and a la carte instances.
 homepage:            https://github.com/cmk/rings
diff --git a/src/Data/Dioid.hs b/src/Data/Dioid.hs
--- a/src/Data/Dioid.hs
+++ b/src/Data/Dioid.hs
@@ -53,5 +53,5 @@
 instance (Monoid a, Monoid b, Dioid a, Dioid b) => Dioid (a, b) where
   fromNatural x = (fromNatural x, fromNatural x)
 
-instance (Monoid a, Monoid b, Monoid c, Dioid a, Dioid b, Dioid c) => Dioid (a, b, c)
+instance (Monoid a, Monoid b, Monoid c, Dioid a, Dioid b, Dioid c) => Dioid (a, b, c) where
   fromNatural x = (fromNatural x, fromNatural x, fromNatural x)
diff --git a/src/Data/Ring.hs b/src/Data/Ring.hs
--- a/src/Data/Ring.hs
+++ b/src/Data/Ring.hs
@@ -2,7 +2,6 @@
     (<<)
   , (><)
   , (<>)
-  , abs
   , negate
   , Ring(..)
 ) where