English
If Ici a is contained in a subset s, then the inclusion from s into α carries atTop to atTop.
Русский
Если Ici a ⊆ s, то включение s → α переносит atTop в atTop.
LaTeX
$$$\forall a,\ (Ici\ a \subseteq s)\Rightarrow \mathrm{map}\left(\mathrm{Subtype.mono}\right)\mathrm{atTop} = \mathrm{atTop}$$$
Lean4
/-- The `atBot` filter for an open interval `Iio a` comes from the `atBot` filter in the ambient
order. -/
@[simp]
theorem map_val_Iio_atBot [Preorder α] [IsDirected α (· ≥ ·)] [NoMinOrder α] (a : α) :
map ((↑) : Iio a → α) atBot = atBot :=
map_val_Ioi_atTop (OrderDual.toDual a)