match two with
| AA.TwoOfThree.oneAndTwo (_ : a ≃ 0) (_ : a ≃ 1) =>
  exact Rel.trans_failR ‹a ≃ 1› one_neqv_zero ‹a ≃ 0›
| AA.TwoOfThree.oneAndThree (_ : a ≃ 0) (_ : a ≃ -1) =>
  exact Rel.trans_failR ‹a ≃ -1› neg_one_neqv_zero ‹a ≃ 0›
| AA.TwoOfThree.twoAndThree (_ : a ≃ 1) (_ : a ≃ -1) =>
  exact Rel.trans_failR ‹a ≃ -1› neg_one_neqv_one ‹a ≃ 1›
ℕ : Type
inst✝⁴ : Natural ℕ
ℤ : Type
inst✝³ : Core ℤ
inst✝² : Addition ℤ
inst✝¹ : Multiplication ℤ
inst✝ : Negation ℤ
a : ℤ
two : AA.TwoOfThree (a ≃ 0) (a ≃ 1) (a ≃ -1)
⊢ False
no goals