diff --git a/Algebra/Affine.hs b/Algebra/Affine.hs
--- a/Algebra/Affine.hs
+++ b/Algebra/Affine.hs
@@ -6,3 +6,12 @@
     type Diff a
     diff :: a -> a -> Diff a
     offset :: Diff a -> a -> a
+
+infix 6 .-.
+(.-.) :: Affine a => a -> a -> Diff a
+(.-.) = diff
+
+infixl 6 .+, .-
+(.+), (.-) :: Affine a => a -> Diff a -> a
+a .+ δ = offset δ a
+a .- δ = offset (invert δ) a
diff --git a/affine.cabal b/affine.cabal
--- a/affine.cabal
+++ b/affine.cabal
@@ -1,5 +1,5 @@
 name:                affine
-version:             0.1.0.0
+version:             0.1.1.0
 synopsis:            Affine spaces (generalized)
 -- description:
 license:             BSD3