diff --git a/algebra.cabal b/algebra.cabal
--- a/algebra.cabal
+++ b/algebra.cabal
@@ -1,6 +1,6 @@
 name:          algebra
 category:      Math, Algebra
-version:       3.0
+version:       3.0.1
 license:       BSD3
 cabal-version: >= 1.6
 license-file:  LICENSE
diff --git a/src/Numeric/Coalgebra/Geometric.hs b/src/Numeric/Coalgebra/Geometric.hs
--- a/src/Numeric/Coalgebra/Geometric.hs
+++ b/src/Numeric/Coalgebra/Geometric.hs
@@ -120,8 +120,8 @@
     p = shiftL 1 c
     mask = (-1) `div` (shiftL 1 p + 1)
 
-m1powTimes :: (Bits n, Group r) => n -> r -> r
-m1powTimes n r 
+m1powTimes :: (Num n, Bits n, Group r) => n -> r -> r
+m1powTimes n r
   | (n .&. 1) == 0 = r
   | otherwise      = negate r