variable p : Nat -> Nat -> Bool
check fun (a b c : Bool) (p : Nat -> Nat -> Bool) (n m : Nat)
          (H : a => b => (forall x y, c => p (x + n) (x + m)))
          (Ha : a)
          (Hb : b)
          (Hc : c),
          H ◂ Ha ◂ Hb ◂ 0 ◂ 1 ◂ Hc