Theorem: PartialHomeomorph.preimage_eventuallyEq_target_inter_preimage_inter
File: Mathlib/Topology/PartialHomeomorph.lean

Proof steps:
state_before: X : Type u_1
X' : Type u_2
Y : Type u_3
Y' : Type u_4
Z : Type u_5
Z' : Type u_6
inst✝⁵ : TopologicalSpace X
inst✝⁴ : TopologicalSpace X'
inst✝³ : TopologicalSpace Y
inst✝² : TopologicalSpace Y'
inst✝¹ : TopologicalSpace Z
inst✝ : TopologicalSpace Z'
e✝ e : PartialHomeomorph X Y
s : Set X
t : Set Z
x : X
f : X → Z
hf : ContinuousWithinAt f s x
hxe : x ∈ e.source
ht : t ∈ 𝓝 (f x)
⊢ ↑e.symm ⁻¹' s =ᶠ[𝓝 (↑e x)] e.target ∩ ↑e.symm ⁻¹' (s ∩ f ⁻¹' t)
state_after: X : Type u_1
X' : Type u_2
Y : Type u_3
Y' : Type u_4
Z : Type u_5
Z' : Type u_6
inst✝⁵ : TopologicalSpace X
inst✝⁴ : TopologicalSpace X'
inst✝³ : TopologicalSpace Y
inst✝² : TopologicalSpace Y'
inst✝¹ : TopologicalSpace Z
inst✝ : TopologicalSpace Z'
e✝ e : PartialHomeomorph X Y
s : Set X
t : Set Z
x : X
f : X → Z
hf : ContinuousWithinAt f s x
hxe : x ∈ e.source
ht : t ∈ 𝓝 (f x)
⊢ ∀ᶠ (x : X) in 𝓝 x, ↑e x ∈ ↑e.symm ⁻¹' s ↔ ↑e x ∈ e.target ∩ ↑e.symm ⁻¹' (s ∩ f ⁻¹' t)
tactic: rw [eventuallyEq_set, e.eventually_nhds _ hxe]
state_before: X : Type u_1
X' : Type u_2
Y : Type u_3
Y' : Type u_4
Z : Type u_5
Z' : Type u_6
inst✝⁵ : TopologicalSpace X
inst✝⁴ : TopologicalSpace X'
inst✝³ : TopologicalSpace Y
inst✝² : TopologicalSpace Y'
inst✝¹ : TopologicalSpace Z
inst✝ : TopologicalSpace Z'
e✝ e : PartialHomeomorph X Y
s : Set X
t : Set Z
x : X
f : X → Z
hf : ContinuousWithinAt f s x
hxe : x ∈ e.source
ht : t ∈ 𝓝 (f x)
⊢ ∀ᶠ (x : X) in 𝓝 x, ↑e x ∈ ↑e.symm ⁻¹' s ↔ ↑e x ∈ e.target ∩ ↑e.symm ⁻¹' (s ∩ f ⁻¹' t)
state_after: case h
X : Type u_1
X' : Type u_2
Y : Type u_3
Y' : Type u_4
Z : Type u_5
Z' : Type u_6
inst✝⁵ : TopologicalSpace X
inst✝⁴ : TopologicalSpace X'
inst✝³ : TopologicalSpace Y
inst✝² : TopologicalSpace Y'
inst✝¹ : TopologicalSpace Z
inst✝ : TopologicalSpace Z'
e✝ e : PartialHomeomorph X Y
s : Set X
t : Set Z
x : X
f : X → Z
hf : ContinuousWithinAt f s x
hxe : x ∈ e.source
ht : t ∈ 𝓝 (f x)
⊢ ∀ a ∈ e.source, (a ∈ s → a ∈ f ⁻¹' t) → (↑e a ∈ ↑e.symm ⁻¹' s ↔ ↑e a ∈ e.target ∩ ↑e.symm ⁻¹' (s ∩ f ⁻¹' t))
tactic: filter_upwards [e.open_source.mem_nhds hxe,
    mem_nhdsWithin_iff_eventually.mp (hf.preimage_mem_nhdsWithin ht)]
state_before: case h
X : Type u_1
X' : Type u_2
Y : Type u_3
Y' : Type u_4
Z : Type u_5
Z' : Type u_6
inst✝⁵ : TopologicalSpace X
inst✝⁴ : TopologicalSpace X'
inst✝³ : TopologicalSpace Y
inst✝² : TopologicalSpace Y'
inst✝¹ : TopologicalSpace Z
inst✝ : TopologicalSpace Z'
e✝ e : PartialHomeomorph X Y
s : Set X
t : Set Z
x : X
f : X → Z
hf : ContinuousWithinAt f s x
hxe : x ∈ e.source
ht : t ∈ 𝓝 (f x)
⊢ ∀ a ∈ e.source, (a ∈ s → a ∈ f ⁻¹' t) → (↑e a ∈ ↑e.symm ⁻¹' s ↔ ↑e a ∈ e.target ∩ ↑e.symm ⁻¹' (s ∩ f ⁻¹' t))
state_after: case h
X : Type u_1
X' : Type u_2
Y : Type u_3
Y' : Type u_4
Z : Type u_5
Z' : Type u_6
inst✝⁵ : TopologicalSpace X
inst✝⁴ : TopologicalSpace X'
inst✝³ : TopologicalSpace Y
inst✝² : TopologicalSpace Y'
inst✝¹ : TopologicalSpace Z
inst✝ : TopologicalSpace Z'
e✝ e : PartialHomeomorph X Y
s : Set X
t : Set Z
x : X
f : X → Z
hf : ContinuousWithinAt f s x
hxe : x ∈ e.source
ht : t ∈ 𝓝 (f x)
y : X
hy : y ∈ e.source
hyu : y ∈ s → y ∈ f ⁻¹' t
⊢ ↑e y ∈ ↑e.symm ⁻¹' s ↔ ↑e y ∈ e.target ∩ ↑e.symm ⁻¹' (s ∩ f ⁻¹' t)
tactic: intro y hy hyu
state_before: case h
X : Type u_1
X' : Type u_2
Y : Type u_3
Y' : Type u_4
Z : Type u_5
Z' : Type u_6
inst✝⁵ : TopologicalSpace X
inst✝⁴ : TopologicalSpace X'
inst✝³ : TopologicalSpace Y
inst✝² : TopologicalSpace Y'
inst✝¹ : TopologicalSpace Z
inst✝ : TopologicalSpace Z'
e✝ e : PartialHomeomorph X Y
s : Set X
t : Set Z
x : X
f : X → Z
hf : ContinuousWithinAt f s x
hxe : x ∈ e.source
ht : t ∈ 𝓝 (f x)
y : X
hy : y ∈ e.source
hyu : y ∈ s → y ∈ f ⁻¹' t
⊢ ↑e y ∈ ↑e.symm ⁻¹' s ↔ ↑e y ∈ e.target ∩ ↑e.symm ⁻¹' (s ∩ f ⁻¹' t)
state_after: no goals
tactic: simp_rw [mem_inter_iff, mem_preimage, mem_inter_iff, e.mapsTo hy, true_and_iff, iff_self_and,
    e.left_inv hy, iff_true_intro hyu]