id : ?M_1 → ?M_1
trans : (?M_1 → ?M_1 → Bool) → Bool
symm : (?M_1 → ?M_1 → Bool) → Bool
equivalence : (?M_1 → ?M_1 → Bool) → Bool
λ (A : Type) (R : A → A → Bool),
  and (and (refl R) (symm R)) (trans R)