English
The lift of the mapped filter is bounded by the original lift: (map m f).lift g ≤ f.lift (g ∘ image m).
Русский
Подъем образованного фильтра ограничивает исходный подъём: (map m f).lift g ≤ f.lift (g ∘ image m).
LaTeX
$$(map m f).lift g ≤ f.lift (g \circ image m)$$
Lean4
theorem lift_map_le {g : Set β → Filter γ} {m : α → β} : (map m f).lift g ≤ f.lift (g ∘ image m) :=
le_lift.2 fun _s hs => lift_le (image_mem_map hs) le_rfl