English
If σ, τ are from range_toPermHom'(g), then a.ofPermHom commutes with multiplication: a.ofPermHom (σ τ) = a.ofPermHom σ ∘ a.ofPermHom τ.
Русский
Если σ, τ из range_toPermHom'(g), то a.ofPermHom сохраняет произведение: a.ofPermHom (σ τ) = a.ofPermHom σ ∘ a.ofPermHom τ.
LaTeX
$$a.ofPermHom (instHMul.hMul σ τ) = MonoidHom.func_like$$
Lean4
theorem ofPermHomFun_one (x : α) : (ofPermHomFun a 1) x = x :=
by
rcases mem_fixedPoints_or_exists_zpow_eq a x with (hx | ⟨c, hc, m, hm⟩)
· rw [ofPermHomFun_apply_of_mem_fixedPoints a _ hx]
· rw [ofPermHomFun_apply_of_cycleOf_mem a _ hc hm, OneMemClass.coe_one, coe_one, id_eq, hm]