English
Map distributes over lift: map m on f.lift g equals f.lift of map m with g composed with map.
Русский
Отображение м распределяет над подъемом: map m над f.lift g равно f.lift (map m ∘ g).
LaTeX
$$map m (f.lift g) = f.lift (map m \circ g)$$
Lean4
theorem map_lift_eq {m : β → γ} (hg : Monotone g) : map m (f.lift g) = f.lift (map m ∘ g) :=
have : Monotone (map m ∘ g) := map_mono.comp hg
Filter.ext fun s => by simp only [mem_lift_sets hg, mem_lift_sets this, mem_map, Function.comp_apply]