Theorem: LinearMap.isOpenMap_of_finiteDimensional
File: Mathlib/Topology/Algebra/Module/FiniteDimension.lean

tactic: rcases f.exists_rightInverse_of_surjective (LinearMap.range_eq_top.2 hf) with ⟨g, hg⟩
state_before: 𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁷ : AddCommGroup E
inst✝¹⁶ : Module 𝕜 E
inst✝¹⁵ : TopologicalSpace E
inst✝¹⁴ : TopologicalAddGroup E
inst✝¹³ : ContinuousSMul 𝕜 E
F : Type w
inst✝¹² : AddCommGroup F
inst✝¹¹ : Module 𝕜 F
inst✝¹⁰ : TopologicalSpace F
inst✝⁹ : TopologicalAddGroup F
inst✝⁸ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁷ : AddCommGroup F'
inst✝⁶ : Module 𝕜 F'
inst✝⁵ : TopologicalSpace F'
inst✝⁴ : TopologicalAddGroup F'
inst✝³ : ContinuousSMul 𝕜 F'
inst✝² : CompleteSpace 𝕜
inst✝¹ : T2Space E
inst✝ : FiniteDimensional 𝕜 E
f : F →ₗ[𝕜] E
hf : Function.Surjective ↑f
⊢ IsOpenMap ↑f

tactic: refine' IsOpenMap.of_sections fun x => ⟨fun y => g (y - f x) + x, _, _, fun y => _⟩
state_before: case intro
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁷ : AddCommGroup E
inst✝¹⁶ : Module 𝕜 E
inst✝¹⁵ : TopologicalSpace E
inst✝¹⁴ : TopologicalAddGroup E
inst✝¹³ : ContinuousSMul 𝕜 E
F : Type w
inst✝¹² : AddCommGroup F
inst✝¹¹ : Module 𝕜 F
inst✝¹⁰ : TopologicalSpace F
inst✝⁹ : TopologicalAddGroup F
inst✝⁸ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁷ : AddCommGroup F'
inst✝⁶ : Module 𝕜 F'
inst✝⁵ : TopologicalSpace F'
inst✝⁴ : TopologicalAddGroup F'
inst✝³ : ContinuousSMul 𝕜 F'
inst✝² : CompleteSpace 𝕜
inst✝¹ : T2Space E
inst✝ : FiniteDimensional 𝕜 E
f : F →ₗ[𝕜] E
hf : Function.Surjective ↑f
g : E →ₗ[𝕜] F
hg : comp f g = id
⊢ IsOpenMap ↑f

tactic: exact
  ((g.continuous_of_finiteDimensional.comp <| continuous_id.sub continuous_const).add
      continuous_const).continuousAt
state_before: case intro.refine'_1
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁷ : AddCommGroup E
inst✝¹⁶ : Module 𝕜 E
inst✝¹⁵ : TopologicalSpace E
inst✝¹⁴ : TopologicalAddGroup E
inst✝¹³ : ContinuousSMul 𝕜 E
F : Type w
inst✝¹² : AddCommGroup F
inst✝¹¹ : Module 𝕜 F
inst✝¹⁰ : TopologicalSpace F
inst✝⁹ : TopologicalAddGroup F
inst✝⁸ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁷ : AddCommGroup F'
inst✝⁶ : Module 𝕜 F'
inst✝⁵ : TopologicalSpace F'
inst✝⁴ : TopologicalAddGroup F'
inst✝³ : ContinuousSMul 𝕜 F'
inst✝² : CompleteSpace 𝕜
inst✝¹ : T2Space E
inst✝ : FiniteDimensional 𝕜 E
f : F →ₗ[𝕜] E
hf : Function.Surjective ↑f
g : E →ₗ[𝕜] F
hg : comp f g = id
x : F
⊢ ContinuousAt (fun y => ↑g (y - ↑f x) + x) (↑f x)

tactic: simp only
state_before: case intro.refine'_2
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁷ : AddCommGroup E
inst✝¹⁶ : Module 𝕜 E
inst✝¹⁵ : TopologicalSpace E
inst✝¹⁴ : TopologicalAddGroup E
inst✝¹³ : ContinuousSMul 𝕜 E
F : Type w
inst✝¹² : AddCommGroup F
inst✝¹¹ : Module 𝕜 F
inst✝¹⁰ : TopologicalSpace F
inst✝⁹ : TopologicalAddGroup F
inst✝⁸ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁷ : AddCommGroup F'
inst✝⁶ : Module 𝕜 F'
inst✝⁵ : TopologicalSpace F'
inst✝⁴ : TopologicalAddGroup F'
inst✝³ : ContinuousSMul 𝕜 F'
inst✝² : CompleteSpace 𝕜
inst✝¹ : T2Space E
inst✝ : FiniteDimensional 𝕜 E
f : F →ₗ[𝕜] E
hf : Function.Surjective ↑f
g : E →ₗ[𝕜] F
hg : comp f g = id
x : F
⊢ (fun y => ↑g (y - ↑f x) + x) (↑f x) = x

tactic: rw [sub_self, map_zero, zero_add]
state_before: case intro.refine'_2
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁷ : AddCommGroup E
inst✝¹⁶ : Module 𝕜 E
inst✝¹⁵ : TopologicalSpace E
inst✝¹⁴ : TopologicalAddGroup E
inst✝¹³ : ContinuousSMul 𝕜 E
F : Type w
inst✝¹² : AddCommGroup F
inst✝¹¹ : Module 𝕜 F
inst✝¹⁰ : TopologicalSpace F
inst✝⁹ : TopologicalAddGroup F
inst✝⁸ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁷ : AddCommGroup F'
inst✝⁶ : Module 𝕜 F'
inst✝⁵ : TopologicalSpace F'
inst✝⁴ : TopologicalAddGroup F'
inst✝³ : ContinuousSMul 𝕜 F'
inst✝² : CompleteSpace 𝕜
inst✝¹ : T2Space E
inst✝ : FiniteDimensional 𝕜 E
f : F →ₗ[𝕜] E
hf : Function.Surjective ↑f
g : E →ₗ[𝕜] F
hg : comp f g = id
x : F
⊢ ↑g (↑f x - ↑f x) + x = x

tactic: simp only [map_sub, map_add, ← comp_apply f g, hg, id_apply, sub_add_cancel]
state_before: case intro.refine'_3
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁷ : AddCommGroup E
inst✝¹⁶ : Module 𝕜 E
inst✝¹⁵ : TopologicalSpace E
inst✝¹⁴ : TopologicalAddGroup E
inst✝¹³ : ContinuousSMul 𝕜 E
F : Type w
inst✝¹² : AddCommGroup F
inst✝¹¹ : Module 𝕜 F
inst✝¹⁰ : TopologicalSpace F
inst✝⁹ : TopologicalAddGroup F
inst✝⁸ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁷ : AddCommGroup F'
inst✝⁶ : Module 𝕜 F'
inst✝⁵ : TopologicalSpace F'
inst✝⁴ : TopologicalAddGroup F'
inst✝³ : ContinuousSMul 𝕜 F'
inst✝² : CompleteSpace 𝕜
inst✝¹ : T2Space E
inst✝ : FiniteDimensional 𝕜 E
f : F →ₗ[𝕜] E
hf : Function.Surjective ↑f
g : E →ₗ[𝕜] F
hg : comp f g = id
x : F
y : E
⊢ ↑f ((fun y => ↑g (y - ↑f x) + x) y) = y