English
Mapping distributes over concatenation: map f (append s t) = append (map f s) (map f t).
Русский
Отображение распределяется над конкатенацией: map f (append s t) = append (map f s) (map f t).
LaTeX
$$$$ \\operatorname{map} f (\\mathrm{append}} s t) = \\mathrm{append}(\\operatorname{map} f s)(\\operatorname{map} f t) $$$$
Lean4
@[simp]
theorem map_append (f : α → β) (s t) : map f (append s t) = append (map f s) (map f t) :=
Seq.map_append _ _ _