English
Inserting at two possibly different keys commutes: (s.insert a b).insert a' b' = (s.insert a' b').insert a b.
Русский
Вставка по двум ключам, возможно разным, коммутирует: (s.insert a b).insert a' b' = (s.insert a' b').insert a b.
LaTeX
$$$ (s.insert a b).insert a' b' = (s.insert a' b').insert a b $$$
Lean4
theorem insert_insert_of_ne {a a'} {b : β a} {b' : β a'} (s : Finmap β) (h : a ≠ a') :
(s.insert a b).insert a' b' = (s.insert a' b').insert a b :=
induction_on s fun s => by simp only [insert_toFinmap, AList.toFinmap_eq, AList.insert_insert_of_ne _ h]