apply Subtype.eq
n : Nat
s : Setoid (Fin n)
inst✝ : DecidableRel Setoid.r
i✝ j✝ : Subtype (repr s)
i : Fin n
hri : (Fin.find? fun b => decide (Setoid.r i b)) = some i
j : Fin n
hrj : (Fin.find? fun b => decide (Setoid.r j b)) = some j
hij : Setoid.r ⟨i, hri⟩.val ⟨j, hrj⟩.val
⊢ ⟨i, hri⟩ = ⟨j, hrj⟩
case a
n : Nat
s : Setoid (Fin n)
inst✝ : DecidableRel Setoid.r
i✝ j✝ : Subtype (repr s)
i : Fin n
hri : (Fin.find? fun b => decide (Setoid.r i b)) = some i
j : Fin n
hrj : (Fin.find? fun b => decide (Setoid.r j b)) = some j
hij : Setoid.r ⟨i, hri⟩.val ⟨j, hrj⟩.val
⊢ ⟨i, hri⟩.val = ⟨j, hrj⟩.val