anchor.diff:         ("let A = id ( true , false ) in (<=> A) = false" :swe "let A = id ( true , false ) in (<=> A) = false" :value '(:|Bool| . t))
          ("(<=> ( true , true )) = true" :swe "(<=> ( true , true )) = true" :value '(:|Bool| . t))
          ("let A = id ( true , true ) in (<=> A) = true" :swe "let A = id ( true , true ) in (<=> A) = true" :value '(:|Bool| . t))
  -       ("[(<=>)(true,true)] = [(<=>)(true,true)]"     :swe "[(<=>)(true,true)] = [(<=>)(true,true)]"     :value '(:|Bool| . t))
  +       ("[(<=>)(true,true)] = [(<=>)(true,true)]"     :swe "[(<=>)(true,true)] = [(<=>)(true,true)]" :value '(:|Bool| . t))
          ;; Boolean [  6]:  op ~=  infixr 20 : fa(a) a * a -> Boolean
          ("(~= ( 4 , 4 )) = false" :swe "(~= ( 4 , 4 )) = false" :value '(:|Bool| . t))
          ("let A = id ( 4 , 4 ) in (~= A) = false" :swe "let A = id ( 4 , 4 ) in (~= A) = false" :value '(:|Bool| . t))
          ("(~= ( 4 , 5 )) = true" :swe "(~= ( 4 , 5 )) = true" :value '(:|Bool| . t))
          ("let A = id ( 4 , 5 ) in (~= A) = true" :swe "let A = id ( 4 , 5 ) in (~= A) = true" :value '(:|Bool| . t))
  -       ("[(~=)(4, 5)] = [(~=)(4, 5)]"     :swe "[(~=)(4, 5)] = [(~=)(4, 5)]"     :value '(:|Bool| . t))
  +       ("[(~=)(4, 5)] = [(~=)(4, 5)]"     :swe "[(~=)(4, 5)] = [(~=)(4, 5)]" :value '(:|Bool| . t))
          ;; Boolean [  7]:  op compare  : Boolean * Boolean -> Comparison
          ("(compare ( false , false )) = Equal" :swe "(compare ( false , false )) = Equal" :value '(:|Bool| . t))
          ("let A = id ( false , false ) in (compare A) = Equal" :swe "let A = id ( false , false ) in (compare A) = Equal" :value '(:|Bool| . t))
  
positive.code:        ("let A = id ( true , false ) in (=> A) = false" :swe "let A = id ( true , false ) in (=> A) = false" :value '(:|Bool| . t))
         ("(=> ( true , true )) = true" :swe "(=> ( true , true )) = true" :value '(:|Bool| . t))
         ("let A = id ( true , true ) in (=> A) = true" :swe "let A = id ( true , true ) in (=> A) = true" :value '(:|Bool| . t))
         ("[(=>)(true,true)] = [(=>)(true,true)]"     :swe "[(=>)(true,true)] = [(=>)(true,true)]"     :value '(:|Bool| . t))
         ;; Boolean [  5]:  op <=> infixr 12 : Boolean * Boolean -> Boolean 
         ("(<=> ( false , false )) = true" :swe "(<=> ( false , false )) = true" :value '(:|Bool| . t))
         ("let A = id ( false , false ) in (<=> A) = true" :swe "let A = id ( false , false ) in (<=> A) = true" :value '(:|Bool| . t))
  
negative.code:        ("(~ ( false )) = true" :swe "(~ ( false )) = true" :value '(:|Bool| . t))
         ("[true, false, (true), (false)] = [(true), (false), true, false]" :swe "[true, false, (true), (false)] = [(true), (false), true, false]" :value '(:|Bool| . t))
         ;; Boolean [  2]:  op ~   : Boolean -> Boolean 
         ("~ true = false"    :swe "~ true = false" :value '(:|Bool| . t))
         ("~ false = true"    :swe "~ false = true" :value '(:|Bool| . t))
         ("~ (~ true) = true"   :swe "~ (~ true) = true" :value '(:|Bool| . t))
         ("~ (~ false) = false" :swe "~ (~ false) = false" :value '(:|Bool| . t))
         ("[(~)(true)] = [(~)(true)]"     :swe "[(~)(true)] = [(~)(true)]" :value '(:|Bool| . t))
         ;; Boolean [  2]:  op &   infixr 15 : Boolean * Boolean -> Boolean 
         ("(&& ( false , false )) = false" :swe "(&& ( false , false )) = false" :value '(:|Bool| . t))
         ("let A = id ( false , false ) in (&& A) = false" :swe "let A = id ( false , false ) in (&& A) = false" :value '(:|Bool| . t))
  