Skip to content

Commit

Permalink
Sebastien's suggestions
Browse files Browse the repository at this point in the history
  • Loading branch information
Nicknamen committed Jun 26, 2021
1 parent 34eeba2 commit 0656d71
Show file tree
Hide file tree
Showing 5 changed files with 17 additions and 11 deletions.
9 changes: 9 additions & 0 deletions src/data/equiv/local_equiv.lean
Original file line number Diff line number Diff line change
Expand Up @@ -368,6 +368,15 @@ lemma source_inter_preimage_inv_preimage (s : set α) :
e.source ∩ e ⁻¹' (e.symm ⁻¹' s) = e.source ∩ s :=
set.ext $ λ x, and.congr_right_iff.2 $ λ hx, by simp only [mem_preimage, e.left_inv hx]

lemma source_inter_preimage_target_inter (s : set β) :
e.source ∩ (e ⁻¹' (e.target ∩ s)) = e.source ∩ (e ⁻¹' s) :=
begin
refine ext_iff.mpr (λ x, ⟨λ hx, _, λ hx, _⟩),
simp only [mem_inter_eq, mem_preimage] at *;
exact ⟨hx.1, hx.2.2⟩,
exact ⟨hx.1, e.map_source hx.1, hx.2⟩, --exacts?
end

lemma target_inter_inv_preimage_preimage (s : set β) :
e.target ∩ e.symm ⁻¹' (e ⁻¹' s) = e.target ∩ s :=
e.symm.source_inter_preimage_inv_preimage _
Expand Down
2 changes: 1 addition & 1 deletion src/topology/continuous_on.lean
Original file line number Diff line number Diff line change
Expand Up @@ -770,7 +770,7 @@ lemma continuous_on.preimage_open_of_open {f : α → β} {s : set α} {t : set
(hf : continuous_on f s) (hs : is_open s) (ht : is_open t) : is_open (s ∩ f⁻¹' t) :=
(continuous_on_open_iff hs).1 hf t ht

lemma continuous_on.open_preimage {f : α → β} {s : set α} {t : set β} (h : continuous_on f s)
lemma continuous_on.is_open_preimage {f : α → β} {s : set α} {t : set β} (h : continuous_on f s)
(hs : is_open s) (hp : f ⁻¹' t ⊆ s) (ht : is_open t) : is_open (f ⁻¹' t) :=
begin
convert (continuous_on_open_iff hs).mp h t ht,
Expand Down
7 changes: 1 addition & 6 deletions src/topology/local_homeomorph.lean
Original file line number Diff line number Diff line change
Expand Up @@ -211,12 +211,7 @@ e.symm.source_inter_preimage_inv_preimage _

lemma source_inter_preimage_target_inter (s : set β) :
e.source ∩ (e ⁻¹' (e.target ∩ s)) = e.source ∩ (e ⁻¹' s) :=
begin
refine ext_iff.mpr (λ x, ⟨λ hx, _, λ hx, _⟩),
simp only [mem_inter_eq, mem_preimage] at *;
exact ⟨hx.1, hx.2.2⟩,
exact ⟨hx.1, e.to_local_equiv.map_source hx.1, hx.2⟩, --exacts?
end
e.to_local_equiv.source_inter_preimage_target_inter s

/-- Two local homeomorphisms are equal when they have equal `to_fun`, `inv_fun` and `source`.
It is not sufficient to have equal `to_fun` and `source`, as this only determines `inv_fun` on
Expand Down
2 changes: 1 addition & 1 deletion src/topology/order.lean
Original file line number Diff line number Diff line change
Expand Up @@ -424,7 +424,7 @@ le_antisymm
(coinduced_le_iff_le_induced.1 $ le_generate_from $ assume s hs,
generate_open.basic _ $ mem_image_of_mem _ hs)

lemma le_induced_generate {α β} [t : topological_space α] {b : set (set β)}
lemma le_induced_generate_from {α β} [t : topological_space α] {b : set (set β)}
{f : α → β} (h : ∀ (a : set β), a ∈ b → is_open (f ⁻¹' a)) : t ≤ induced f (generate_from b) :=
begin
rw induced_generate_from_eq,
Expand Down
8 changes: 5 additions & 3 deletions src/topology/topological_fiber_bundle.lean
Original file line number Diff line number Diff line change
Expand Up @@ -912,8 +912,10 @@ lemma local_triv'_trans (i j : ι) :
(Z.local_triv' i).symm.trans (Z.local_triv' j) ≈ (Z.triv_change i j).to_local_equiv :=
begin
split,
{ ext x, erw [mem_prod], simp only [mem_local_triv'_source, mem_local_triv'_target,
local_triv'_symm_apply] with mfld_simps},
{ ext x,
erw [mem_prod],
simp only [mem_local_triv'_source, mem_local_triv'_target, local_triv'_symm_apply]
with mfld_simps, },
{ rintros ⟨x, v⟩ hx,
simp only [triv_change, local_triv', local_equiv.symm, true_and, prod_mk_mem_set_prod_eq,
local_equiv.trans_source, mem_inter_eq, and_true, mem_univ, prod.mk.inj_iff, mem_preimage,
Expand Down Expand Up @@ -1102,7 +1104,7 @@ lemma continuous_sigma_mk (b : B) : @continuous _ _ _ (Z.to_topological_space ι
(λ a, (⟨b, a⟩ : (bundle.total_space Z.fiber))) :=
begin
rw [continuous_iff_le_induced, topological_fiber_bundle_core.to_topological_space],
apply le_induced_generate,
apply le_induced_generate_from,
simp only [mem_Union, mem_singleton_iff, local_triv'_source, local_triv'_coe, mem_image],
rintros s ⟨i, t, ht, rfl⟩,
rw [←(local_homeomorph.source_inter_preimage_target_inter (Z.local_triv i) t),
Expand Down

0 comments on commit 0656d71

Please sign in to comment.