Theorem: Subspace.dualAnnihilator_iInf_eq
File: Mathlib/LinearAlgebra/Dual.lean

tactic: revert ι
state_before: K : Type uK
inst✝⁵ : Field K
V₁ : Type uV₁
V₂ : Type uV₂
inst✝⁴ : AddCommGroup V₁
inst✝³ : Module K V₁
inst✝² : AddCommGroup V₂
inst✝¹ : Module K V₂
ι : Type u_1
inst✝ : _root_.Finite ι
W : ι → Subspace K V₁
⊢ dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)
state_after: K : Type uK
inst✝⁴ : Field K
V₁ : Type uV₁
V₂ : Type uV₂
inst✝³ : AddCommGroup V₁
inst✝² : Module K V₁
inst✝¹ : AddCommGroup V₂
inst✝ : Module K V₂
⊢ ∀ {ι : Type u_1} [inst : _root_.Finite ι] (W : ι → Subspace K V₁),
    dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)

tactic: apply Finite.induction_empty_option
state_before: K : Type uK
inst✝⁴ : Field K
V₁ : Type uV₁
V₂ : Type uV₂
inst✝³ : AddCommGroup V₁
inst✝² : Module K V₁
inst✝¹ : AddCommGroup V₂
inst✝ : Module K V₂
⊢ ∀ {ι : Type u_1} [inst : _root_.Finite ι] (W : ι → Subspace K V₁),
    dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)
state_after: case of_equiv
K : Type uK
inst✝⁴ : Field K
V₁ : Type uV₁
V₂ : Type uV₂
inst✝³ : AddCommGroup V₁
inst✝² : Module K V₁
inst✝¹ : AddCommGroup V₂
inst✝ : Module K V₂
⊢ ∀ {α β : Type u_1},
    α ≃ β →
      (∀ (W : α → Subspace K V₁), dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)) →
        ∀ (W : β → Subspace K V₁), dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)

case h_empty
K : Type uK
inst✝⁴ : Field K
V₁ : Type uV₁
V₂ : Type uV₂
inst✝³ : AddCommGroup V₁
inst✝² : Module K V₁
inst✝¹ : AddCommGroup V₂
inst✝ : Module K V₂
⊢ ∀ (W : PEmpty.{u_1 + 1} → Subspace K V₁), dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)

case h_option
K : Type uK
inst✝⁴ : Field K
V₁ : Type uV₁
V₂ : Type uV₂
inst✝³ : AddCommGroup V₁
inst✝² : Module K V₁
inst✝¹ : AddCommGroup V₂
inst✝ : Module K V₂
⊢ ∀ {α : Type u_1} [inst : Fintype α],
    (∀ (W : α → Subspace K V₁), dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)) →
      ∀ (W : Option α → Subspace K V₁), dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)

tactic: intro α β h hyp W
state_before: case of_equiv
K : Type uK
inst✝⁴ : Field K
V₁ : Type uV₁
V₂ : Type uV₂
inst✝³ : AddCommGroup V₁
inst✝² : Module K V₁
inst✝¹ : AddCommGroup V₂
inst✝ : Module K V₂
⊢ ∀ {α β : Type u_1},
    α ≃ β →
      (∀ (W : α → Subspace K V₁), dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)) →
        ∀ (W : β → Subspace K V₁), dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)
state_after: case of_equiv
K : Type uK
inst✝⁴ : Field K
V₁ : Type uV₁
V₂ : Type uV₂
inst✝³ : AddCommGroup V₁
inst✝² : Module K V₁
inst✝¹ : AddCommGroup V₂
inst✝ : Module K V₂
α β : Type u_1
h : α ≃ β
hyp : ∀ (W : α → Subspace K V₁), dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)
W : β → Subspace K V₁
⊢ dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)

tactic: rw [← h.iInf_comp, hyp _, ← h.iSup_comp]
state_before: case of_equiv
K : Type uK
inst✝⁴ : Field K
V₁ : Type uV₁
V₂ : Type uV₂
inst✝³ : AddCommGroup V₁
inst✝² : Module K V₁
inst✝¹ : AddCommGroup V₂
inst✝ : Module K V₂
α β : Type u_1
h : α ≃ β
hyp : ∀ (W : α → Subspace K V₁), dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)
W : β → Subspace K V₁
⊢ dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)
state_after: no goals

tactic: intro W
state_before: case h_empty
K : Type uK
inst✝⁴ : Field K
V₁ : Type uV₁
V₂ : Type uV₂
inst✝³ : AddCommGroup V₁
inst✝² : Module K V₁
inst✝¹ : AddCommGroup V₂
inst✝ : Module K V₂
⊢ ∀ (W : PEmpty.{u_1 + 1} → Subspace K V₁), dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)
state_after: case h_empty
K : Type uK
inst✝⁴ : Field K
V₁ : Type uV₁
V₂ : Type uV₂
inst✝³ : AddCommGroup V₁
inst✝² : Module K V₁
inst✝¹ : AddCommGroup V₂
inst✝ : Module K V₂
W : PEmpty.{u_1 + 1} → Subspace K V₁
⊢ dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)

tactic: rw [iSup_of_empty', iInf_of_isEmpty, sInf_empty, sSup_empty, dualAnnihilator_top]
state_before: case h_empty
K : Type uK
inst✝⁴ : Field K
V₁ : Type uV₁
V₂ : Type uV₂
inst✝³ : AddCommGroup V₁
inst✝² : Module K V₁
inst✝¹ : AddCommGroup V₂
inst✝ : Module K V₂
W : PEmpty.{u_1 + 1} → Subspace K V₁
⊢ dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)
state_after: no goals

tactic: intro α _ h W
state_before: case h_option
K : Type uK
inst✝⁴ : Field K
V₁ : Type uV₁
V₂ : Type uV₂
inst✝³ : AddCommGroup V₁
inst✝² : Module K V₁
inst✝¹ : AddCommGroup V₂
inst✝ : Module K V₂
⊢ ∀ {α : Type u_1} [inst : Fintype α],
    (∀ (W : α → Subspace K V₁), dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)) →
      ∀ (W : Option α → Subspace K V₁), dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)
state_after: case h_option
K : Type uK
inst✝⁵ : Field K
V₁ : Type uV₁
V₂ : Type uV₂
inst✝⁴ : AddCommGroup V₁
inst✝³ : Module K V₁
inst✝² : AddCommGroup V₂
inst✝¹ : Module K V₂
α : Type u_1
inst✝ : Fintype α
h : ∀ (W : α → Subspace K V₁), dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)
W : Option α → Subspace K V₁
⊢ dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)

tactic: rw [iInf_option, iSup_option, dualAnnihilator_inf_eq, h]
state_before: case h_option
K : Type uK
inst✝⁵ : Field K
V₁ : Type uV₁
V₂ : Type uV₂
inst✝⁴ : AddCommGroup V₁
inst✝³ : Module K V₁
inst✝² : AddCommGroup V₂
inst✝¹ : Module K V₂
α : Type u_1
inst✝ : Fintype α
h : ∀ (W : α → Subspace K V₁), dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)
W : Option α → Subspace K V₁
⊢ dualAnnihilator (⨅ i, W i) = ⨆ i, dualAnnihilator (W i)
state_after: no goals