prop_tnorm :: (Ord a, Num a, Show a, Arbitrary a) => (a -> a -> a) -> PropBox
prop_tnorm f = propGroup "t-norm" 
                      [ prop_monoid       1 f 
                      , prop_commutative    f      
                      , prop_monotonic      f  
                      , prop_annihilation 0 f 
                      ]
prop_tnorm :: (Ord a, Num a, Show a, Arbitrary a) => (a -> a -> a) -> PropBox
prop_tnorm f = propGroup "t-norm" 
                      [ prop_monoid       1 f 
                      , prop_commutative    f      
                      , prop_monotonic      f  
                      , prop_annihilation 0 f 
                      ]
prop_tnorm f = propGroup "t-norm" 
                      [ prop_monoid       1 f 
                      , prop_commutative    f      
                      , prop_monotonic      f  
                      , prop_annihilation 0 f 
                      ]