by_contradiction
| assuming hne =>
  cases Connex.connex (r:=r) hne with
  | inl hxy => absurd hxy; exact cyx
  | inr hyx => absurd hyx; exact cxy
α : Sort u_1
r : α → α → Prop
self : LinearOrder r
inst✝ : StableEq α
x y : α
cxy : coRel r x y
cyx : coRel r y x
⊢ x = y
no goals