Set: pp::colors
  Set: pp::unicode
  Assumed: a
  Assumed: b
  Assumed: c
a = 1 ∧ (¬ b = 0 ∨ c ≠ 0)
and_congr
    (refl (a = 1))
    (λ C::1 : a = 1,
       or_congr (refl (¬ b = 0))
                (λ C::2 : ¬ ¬ b = 0,
                   trans (or_congr (refl (c ≠ 0))
                                   (λ C::3 : ¬ c ≠ 0,
                                      congr (congr2 Nat::gt
                                                    (congr (congr2 Nat::add (not_not_elim C::2)) (not_neq_elim C::3)))
                                            C::1))
                         (or_falsel (c ≠ 0))))
a = 1 ∧ (¬ b = 0 ∨ c ≠ 0 ∨ b + c > a) ↔ a = 1 ∧ (¬ b = 0 ∨ c ≠ 0)