diff --git a/Data/BitSet.hs b/Data/BitSet.hs
--- a/Data/BitSet.hs
+++ b/Data/BitSet.hs
@@ -1,12 +1,9 @@
-{-# LANGUAGE FlexibleInstances #-}
-
 module Data.BitSet where
 
 import Control.Applicative
 import Control.Monad (guard)
 import Data.Bits
 import Data.Maybe
-import Data.Semigroup (Max (..), Min (..))
 import Prelude ((==))
 import qualified Prelude as Base
 import Util
@@ -39,24 +36,3 @@
 
 (.&?¬) :: (PartialOrd a, Bits a) => a -> a -> Maybe a
 a .&?¬ b = a .&¬ b <$ guard (b ≤ a)
-
-instance Bits a => Monus (BitSet a) where monus = (.&¬)
-
-{-
-instance {-# OVERLAPPING #-} Bits a => Semigroup (Min (BitSet a)) where Min a <> Min b = Min (a .&. b)
-instance {-# OVERLAPPING #-} Bits a => Semigroup (Max (BitSet a)) where Max a <> Max b = Max (a .|. b)
-
-instance Bits a => Abelian (Min (BitSet a))
-instance Bits a => Abelian (Max (BitSet a))
-
-instance Bits a => Idempotent (Min (BitSet a))
-instance Bits a => Idempotent (Max (BitSet a))
-
-instance Bits a => Monoid (Min (BitSet a)) where
-    mappend = (<>)
-    mempty = Min (complement zeroBits)
-
-instance Bits a => Monoid (Max (BitSet a)) where
-    mappend = (<>)
-    mempty = Max zeroBits
--}
diff --git a/alg.cabal b/alg.cabal
--- a/alg.cabal
+++ b/alg.cabal
@@ -1,5 +1,5 @@
 name:                alg
-version:             0.2.4.0
+version:             0.2.4.1
 synopsis:            Algebraic structures
 -- description:         
 license:             BSD3