diff --git a/examples/Lists.hs b/examples/Lists.hs
--- a/examples/Lists.hs
+++ b/examples/Lists.hs
@@ -7,8 +7,8 @@
 lists :: forall a. (Typeable a, Ord a, Arbitrary a, CoArbitrary a) =>
          a -> [Sig]
 lists a = [
-  -- arith (undefined :: Int),
-  -- funs (undefined :: a),
+  arith (undefined :: Int),
+  funs (undefined :: a),
 
   ["x", "y", "z"] `vars` (undefined :: a),
   ["xs", "ys", "zs"] `vars` (undefined :: [a]),
@@ -17,13 +17,13 @@
   "[]"      `fun0` ([]      :: [a]),
   ":"       `fun2` ((:)     :: a -> [a] -> [a])],
 
-  -- "head"    `fun1` (head    :: [a] -> a),
-  -- "tail"    `fun1` (tail    :: [a] -> [a]),
-  -- "unit"    `fun1` (return  :: a -> [a]),
+  "head"    `fun1` (head    :: [a] -> a),
+  "tail"    `fun1` (tail    :: [a] -> [a]),
+  "unit"    `fun1` (return  :: a -> [a]),
   "++"      `fun2` ((++)    :: [a] -> [a] -> [a]),
-  -- "length"  `fun1` (length  :: [a] -> Int),
-  "reverse" `fun1` (reverse :: [a] -> [a])
-  -- "map"     `fun2` (map     :: (a -> a) -> [a] -> [a])
+  "length"  `fun1` (length  :: [a] -> Int),
+  "reverse" `fun1` (reverse :: [a] -> [a]),
+  "map"     `fun2` (map     :: (a -> a) -> [a] -> [a])
   ]
 
 main = quickSpec (lists (undefined :: A))
diff --git a/quickspec.cabal b/quickspec.cabal
--- a/quickspec.cabal
+++ b/quickspec.cabal
@@ -1,5 +1,5 @@
 Name:                quickspec
-Version:             0.9.4
+Version:             0.9.5
 Cabal-version:       >=1.6
 Build-type:          Simple
 
@@ -91,4 +91,4 @@
 
   Build-depends:
     base < 5, containers, transformers, QuickCheck >= 2.7,
-    random, spoon >= 0.2, array, ghc-prim, mtl, unordered-containers
+    random, spoon >= 0.2, array, ghc-prim, mtl
diff --git a/src/Test/QuickSpec/Reasoning/UnionFind.hs b/src/Test/QuickSpec/Reasoning/UnionFind.hs
--- a/src/Test/QuickSpec/Reasoning/UnionFind.hs
+++ b/src/Test/QuickSpec/Reasoning/UnionFind.hs
@@ -8,15 +8,10 @@
 import Data.IntMap(IntMap)
 import qualified Data.IntMap as IntMap
 
-data Info = Rep Int | NonRep Int
-
-defaultInfo :: Info
-defaultInfo = Rep 1
-
 data S = S {
-  info :: IntMap Info,
-  sym :: Int
-  }
+      links :: IntMap Int,
+      sym :: Int
+    }
 
 type UF = State S
 data Replacement = Int :> Int
@@ -33,9 +28,9 @@
 initial :: Int -> S
 initial n = S IntMap.empty n
 
-modifyInfo f = modify (\s -> s { info = f (info s) })
+modifyLinks f = modify (\s -> s { links = f (links s) })
 modifySym f = modify (\s -> s { sym = f (sym s) })
-putInfo i = modifyInfo (const i)
+putLinks l = modifyLinks (const l)
 
 newSym :: UF Int
 newSym = do
@@ -48,19 +43,10 @@
 s =:= t = do
   rs <- rep s
   rt <- rep t
-  if (rs /= rt) then fmap Just (unifyRep rs rt) else return Nothing
-
-unifyRep :: Int -> Int -> UF Replacement
-unifyRep s t = do
-  ss <- gets (IntMap.findWithDefault 0 s . reps)
-  st <- gets (IntMap.findWithDefault 0 t . reps)
-  if ss <= st then replace s t ss st else replace t s st ss
-
-replace :: Int -> Int -> Int -> Int -> UF Replacement
-replace s t ss st = do
-  modifyReps (IntMap.delete s . IntMap.insert t (ss+st+1))
-  modifyLinks (IntMap.insert s t)
-  return (s :> t)
+  if (rs /= rt) then do
+    modifyLinks (IntMap.insert rs rt)
+    return (Just (rs :> rt))
+   else return Nothing
 
 rep :: Int -> UF Int
 rep t = do