cleanup

collatz.hs

@@ -15,16 +15,6 @@ data Z
 data Nil
 data Cons h t
 
-class Not t b | t -> b
-instance Not True False
-instance Not False True
-
-class And a b r | a b -> r
-instance And True True True
-instance And True False False
-instance And False True False
-instance And False False False
-
 class Equal a b t | a b -> t
 instance Equal Z Z True
 instance Equal (S a) Z False
@@ -53,10 +43,6 @@ class ThreeEnPlusOne x v | x -> v
 instance (Mul (S (S (S Z))) x Z i)
    => ThreeEnPlusOne x (S i)
 
-class If c t f r | c t f -> r
-instance If True t f t
-instance If False t f f
-
 class EqOne x r | x -> r
 instance (Equal x (S Z) b)
    => EqOne x b
@@ -67,10 +53,6 @@ instance IsEven (S Z) False
 instance (IsEven n r)
    => IsEven (S (S n)) r
 
-class IsOdd a b | a -> b
-instance (IsEven a i, Not i r)
-   => IsOdd a r
-
 class Branch b h n | b h -> n
 instance (Half h Z r)
    => Branch True h r