English
For i,j ∈ β, sumCongr 1 (swap i j) equals swap on the right embedded: swap (Sum.inr i) (Sum.inr j).
Русский
Для i,j ∈ β, sumCongr 1 (swap i j) = swap (Sum.inr i) (Sum.inr j).
LaTeX
$$$$sumCongr (1 : Perm \\alpha) (Equiv.swap i j) = Equiv.swap (Sum.inr i) (Sum.inr j).$$$$
Lean4
@[simp]
theorem sumCongr_one_swap {α β : Type*} [DecidableEq α] [DecidableEq β] (i j : β) :
sumCongr (1 : Perm α) (Equiv.swap i j) = Equiv.swap (Sum.inr i) (Sum.inr j) :=
sumCongr_refl_swap i j