-- Mathlib/Topology/VectorBundle/Basic.lean
theorem comp_continuousLinearEquivAt_eq_coord_change (e e' : Trivialization F (π F E))
    [e.IsLinear R] [e'.IsLinear R] {b : B} (hb : b ∈ e.baseSet ∩ e'.baseSet) :
    (e.continuousLinearEquivAt R b hb.1).symm.trans (e'.continuousLinearEquivAt R b hb.2) =
      coordChangeL R e e' b

Proof state:
case h.h
R : Type u_1
B : Type u_2
F : Type u_3
E : B → Type u_4
inst✝¹⁰ : NontriviallyNormedField R
inst✝⁹ : (x : B) → AddCommMonoid (E x)
inst✝⁸ : (x : B) → Module R (E x)
inst✝⁷ : NormedAddCommGroup F
inst✝⁶ : NormedSpace R F
inst✝⁵ : TopologicalSpace B
inst✝⁴ : TopologicalSpace (TotalSpace F E)
inst✝³ : (x : B) → TopologicalSpace (E x)
inst✝² : FiberBundle F E
e e' : Trivialization F TotalSpace.proj
inst✝¹ : Trivialization.IsLinear R e
inst✝ : Trivialization.IsLinear R e'
b : B
hb : b ∈ e.baseSet ∩ e'.baseSet
v : F
⊢ ((continuousLinearEquivAt R e b ⋯).symm.trans (continuousLinearEquivAt R e' b ⋯)) v =
    (↑e' { proj := b, snd := e.symm b v }).2

Tactic:
rfl

Result:
no goals

Proof state:
R : Type u_1
B : Type u_2
F : Type u_3
E : B → Type u_4
inst✝¹⁰ : NontriviallyNormedField R
inst✝⁹ : (x : B) → AddCommMonoid (E x)
inst✝⁸ : (x : B) → Module R (E x)
inst✝⁷ : NormedAddCommGroup F
inst✝⁶ : NormedSpace R F
inst✝⁵ : TopologicalSpace B
inst✝⁴ : TopologicalSpace (TotalSpace F E)
inst✝³ : (x : B) → TopologicalSpace (E x)
inst✝² : FiberBundle F E
e e' : Trivialization F TotalSpace.proj
inst✝¹ : Trivialization.IsLinear R e
inst✝ : Trivialization.IsLinear R e'
b : B
hb : b ∈ e.baseSet ∩ e'.baseSet
⊢ (continuousLinearEquivAt R e b ⋯).symm.trans (continuousLinearEquivAt R e' b ⋯) = coordChangeL R e e' b

Tactic:
ext v

Result:
case h.h
R : Type u_1
B : Type u_2
F : Type u_3
E : B → Type u_4
inst✝¹⁰ : NontriviallyNormedField R
inst✝⁹ : (x : B) → AddCommMonoid (E x)
inst✝⁸ : (x : B) → Module R (E x)
inst✝⁷ : NormedAddCommGroup F
inst✝⁶ : NormedSpace R F
inst✝⁵ : TopologicalSpace B
inst✝⁴ : TopologicalSpace (TotalSpace F E)
inst✝³ : (x : B) → TopologicalSpace (E x)
inst✝² : FiberBundle F E
e e' : Trivialization F TotalSpace.proj
inst✝¹ : Trivialization.IsLinear R e
inst✝ : Trivialization.IsLinear R e'
b : B
hb : b ∈ e.baseSet ∩ e'.baseSet
v : F
⊢ ((continuousLinearEquivAt R e b ⋯).symm.trans (continuousLinearEquivAt R e' b ⋯)) v = (coordChangeL R e e' b) v

Proof state:
case h.h
R : Type u_1
B : Type u_2
F : Type u_3
E : B → Type u_4
inst✝¹⁰ : NontriviallyNormedField R
inst✝⁹ : (x : B) → AddCommMonoid (E x)
inst✝⁸ : (x : B) → Module R (E x)
inst✝⁷ : NormedAddCommGroup F
inst✝⁶ : NormedSpace R F
inst✝⁵ : TopologicalSpace B
inst✝⁴ : TopologicalSpace (TotalSpace F E)
inst✝³ : (x : B) → TopologicalSpace (E x)
inst✝² : FiberBundle F E
e e' : Trivialization F TotalSpace.proj
inst✝¹ : Trivialization.IsLinear R e
inst✝ : Trivialization.IsLinear R e'
b : B
hb : b ∈ e.baseSet ∩ e'.baseSet
v : F
⊢ ((continuousLinearEquivAt R e b ⋯).symm.trans (continuousLinearEquivAt R e' b ⋯)) v = (coordChangeL R e e' b) v

Tactic:
rw [coordChangeL_apply e e' hb]

Result:
case h.h
R : Type u_1
B : Type u_2
F : Type u_3
E : B → Type u_4
inst✝¹⁰ : NontriviallyNormedField R
inst✝⁹ : (x : B) → AddCommMonoid (E x)
inst✝⁸ : (x : B) → Module R (E x)
inst✝⁷ : NormedAddCommGroup F
inst✝⁶ : NormedSpace R F
inst✝⁵ : TopologicalSpace B
inst✝⁴ : TopologicalSpace (TotalSpace F E)
inst✝³ : (x : B) → TopologicalSpace (E x)
inst✝² : FiberBundle F E
e e' : Trivialization F TotalSpace.proj
inst✝¹ : Trivialization.IsLinear R e
inst✝ : Trivialization.IsLinear R e'
b : B
hb : b ∈ e.baseSet ∩ e'.baseSet
v : F
⊢ ((continuousLinearEquivAt R e b ⋯).symm.trans (continuousLinearEquivAt R e' b ⋯)) v =
    (↑e' { proj := b, snd := e.symm b v }).2