max expr size  =    5
  |- on ineqs  =    4
  |- on conds  =    4
max  #-tests   =  500
min  #-tests   =   25  (to consider p ==> q true)
max  #-vars    =    2  (for inequational and conditional laws)

_ :: Bool  (holes: Bool)
_ :: Int  (holes: Int)
_ :: Set Int  (holes: Set Int)
emptyS :: Set Int
singleS :: Int -> Set Int
insertS :: Int -> Set Int -> Set Int
deleteS :: Int -> Set Int -> Set Int
sizeS :: Set Int -> Int
(<~) :: Int -> Set Int -> Bool
(\/) :: Set Int -> Set Int -> Set Int
(/\) :: Set Int -> Set Int -> Set Int
False :: Bool
True :: Bool
(==) :: Bool -> Bool -> Bool
(==) :: Int -> Int -> Bool
(==) :: Set Int -> Set Int -> Bool

                  x <~ emptyS == False
               x <~ singleS x == True
        (emptyS == singleS x) == False
             x <~ insertS x s == True
             x <~ deleteS x s == False
      (emptyS == insertS x s) == False
                     (x == y) == x <~ singleS y
           (s == insertS x s) == x <~ s
               x <~ singleS y == y <~ singleS x
     (singleS x == singleS y) == x <~ singleS y
                (s /\ t == s) == (t == s \/ t)
           (s == deleteS x s) == (False == x <~ s)
            sizeS (singleS x) == sizeS (singleS y)
sizeS (deleteS x (singleS y)) == sizeS (deleteS y (singleS x))
                       s \/ s == s
                       s /\ s == s
                  s \/ emptyS == s
             deleteS x emptyS == emptyS
                  s /\ emptyS == emptyS
             insertS x emptyS == singleS x
        deleteS x (singleS x) == emptyS
                       s \/ t == t \/ s
                       s /\ t == t /\ s
             s \/ deleteS x s == s
                s \/ (s /\ t) == s
             s /\ insertS x s == s
                s /\ (s \/ t) == s
        insertS x (singleS x) == singleS x
               s \/ singleS x == insertS x s
      insertS x (insertS x s) == insertS x s
      deleteS x (deleteS x s) == deleteS x s
      insertS x (deleteS x s) == insertS x s
      deleteS x (insertS x s) == deleteS x s
        insertS x (singleS y) == insertS y (singleS x)
      insertS x (insertS y s) == insertS y (insertS x s)
      deleteS x (deleteS y s) == deleteS y (deleteS x s)
                (s \/ t) \/ u == s \/ (t \/ u)
                (s /\ t) /\ u == s /\ (t /\ u)
             s \/ insertS x t == insertS x (s \/ t)
             s /\ deleteS x t == deleteS x (s /\ t)

          s == singleS x ==> x <~ s
            sizeS emptyS <=  sizeS s
                 sizeS s <=  sizeS (insertS x s)
                 sizeS s <=  sizeS (s \/ t)
     sizeS (deleteS x s) <=  sizeS s
          sizeS (s /\ t) <=  sizeS s
       sizeS (singleS x) <=  sizeS (insertS y s)
     sizeS (deleteS x s) <=  sizeS (t \/ s)
                  emptyS <=  s
   deleteS x (singleS y) <=  singleS y
          s /\ singleS x <=  singleS x
  singleS (sizeS emptyS) <=  singleS (sizeS s)
insertS (sizeS emptyS) s <=  singleS (sizeS s)
insertS (sizeS emptyS) s <=  singleS (sizeS (singleS x))