English
For any f: α → β and a ≃ α, composing with the update operation satisfies a compatibility: update f a v ∘ g = update (f ∘ g) (g^{-1} a) v.
Русский
Для любого f: α → β и geë α эквивалентности g, композиция с обновлением удовлетворяет совместимости: update f a v ∘ g = update (f ∘ g) g^{-1}(a) v.
LaTeX
$$$\\text{update }f\\ a\\ v\\circ g = \\text{update }(f\\circ g)\\ (g^{-1} a)\\ v.$$$
Lean4
theorem update_apply_equiv_apply [DecidableEq α'] [DecidableEq α] (f : α → β) (g : α' ≃ α) (a : α) (v : β) (a' : α') :
update f a v (g a') = update (f ∘ g) (g.symm a) v a' :=
congr_fun (update_comp_equiv f g a v) a'