English
As above, TotalSpace.mk b (e.symm b y) equals the inverse image under the open partial homeomorph.
Русский
Как выше, TotalSpace.mk b (e.symm b y) равняется обратному изображению под открытым частичным гомоморфом.
LaTeX
$$$TotalSpace.mk\\, b\\, (e.symm\\, b\\, y) = e.toOpenPartialHomeomorph.symm (b, y)$$$
Lean4
theorem continuousOn_symm (e : Trivialization F (π F E)) :
ContinuousOn (fun z : B × F => TotalSpace.mk' F z.1 (e.symm z.1 z.2)) (e.baseSet ×ˢ univ) :=
by
have : ∀ z ∈ e.baseSet ×ˢ (univ : Set F), TotalSpace.mk z.1 (e.symm z.1 z.2) = e.toOpenPartialHomeomorph.symm z :=
by
rintro x ⟨hx : x.1 ∈ e.baseSet, _⟩
rw [e.mk_symm hx]
refine ContinuousOn.congr ?_ this
rw [← e.target_eq]
exact e.toOpenPartialHomeomorph.continuousOn_symm