Theorem: isIrreducible_iff_sUnion_closed
File: Mathlib/Topology/Irreducible.lean

tactic: simp only [isIrreducible_iff_sInter]
state_before: X : Type u_1
Y : Type u_2
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
s t : Set X
⊢ IsIrreducible s ↔ ∀ (t : Finset (Set X)), (∀ z ∈ t, IsClosed z) → s ⊆ ⋃₀ ↑t → ∃ z ∈ t, s ⊆ z
state_after: X : Type u_1
Y : Type u_2
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
s t : Set X
⊢ (∀ (U : Finset (Set X)), (∀ u ∈ U, IsOpen u) → (∀ u ∈ U, (s ∩ u).Nonempty) → (s ∩ ⋂₀ ↑U).Nonempty) ↔
    ∀ (t : Finset (Set X)), (∀ z ∈ t, IsClosed z) → s ⊆ ⋃₀ ↑t → ∃ z ∈ t, s ⊆ z

tactic: refine ((@compl_involutive (Set X) _).toPerm _).finsetCongr.forall_congr fun {t} => ?_
state_before: X : Type u_1
Y : Type u_2
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
s t : Set X
⊢ (∀ (U : Finset (Set X)), (∀ u ∈ U, IsOpen u) → (∀ u ∈ U, (s ∩ u).Nonempty) → (s ∩ ⋂₀ ↑U).Nonempty) ↔
    ∀ (t : Finset (Set X)), (∀ z ∈ t, IsClosed z) → s ⊆ ⋃₀ ↑t → ∃ z ∈ t, s ⊆ z
state_after: X : Type u_1
Y : Type u_2
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
s t✝ : Set X
t : Finset (Set X)
⊢ (∀ u ∈ t, IsOpen u) → (∀ u ∈ t, (s ∩ u).Nonempty) → (s ∩ ⋂₀ ↑t).Nonempty ↔
    (∀ z ∈ (Equiv.finsetCongr (Function.Involutive.toPerm compl ⋯)) t, IsClosed z) →
      s ⊆ ⋃₀ ↑((Equiv.finsetCongr (Function.Involutive.toPerm compl ⋯)) t) →
        ∃ z ∈ (Equiv.finsetCongr (Function.Involutive.toPerm compl ⋯)) t, s ⊆ z

tactic: simp_rw [Equiv.finsetCongr_apply, Finset.forall_mem_map, Finset.mem_map, Finset.coe_map,
  sUnion_image, Equiv.coe_toEmbedding, Function.Involutive.coe_toPerm, isClosed_compl_iff,
  exists_exists_and_eq_and]
state_before: X : Type u_1
Y : Type u_2
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
s t✝ : Set X
t : Finset (Set X)
⊢ (∀ u ∈ t, IsOpen u) → (∀ u ∈ t, (s ∩ u).Nonempty) → (s ∩ ⋂₀ ↑t).Nonempty ↔
    (∀ z ∈ (Equiv.finsetCongr (Function.Involutive.toPerm compl ⋯)) t, IsClosed z) →
      s ⊆ ⋃₀ ↑((Equiv.finsetCongr (Function.Involutive.toPerm compl ⋯)) t) →
        ∃ z ∈ (Equiv.finsetCongr (Function.Involutive.toPerm compl ⋯)) t, s ⊆ z
state_after: X : Type u_1
Y : Type u_2
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
s t✝ : Set X
t : Finset (Set X)
⊢ (∀ u ∈ t, IsOpen u) → (∀ u ∈ t, (s ∩ u).Nonempty) → (s ∩ ⋂₀ ↑t).Nonempty ↔
    (∀ u ∈ t, IsOpen u) → s ⊆ ⋃ x ∈ ↑t, xᶜ → ∃ a ∈ t, s ⊆ aᶜ

tactic: refine forall_congr' fun _ => Iff.trans ?_ not_imp_not
state_before: X : Type u_1
Y : Type u_2
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
s t✝ : Set X
t : Finset (Set X)
⊢ (∀ u ∈ t, IsOpen u) → (∀ u ∈ t, (s ∩ u).Nonempty) → (s ∩ ⋂₀ ↑t).Nonempty ↔
    (∀ u ∈ t, IsOpen u) → s ⊆ ⋃ x ∈ ↑t, xᶜ → ∃ a ∈ t, s ⊆ aᶜ
state_after: X : Type u_1
Y : Type u_2
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
s t✝ : Set X
t : Finset (Set X)
x✝ : ∀ u ∈ t, IsOpen u
⊢ (∀ u ∈ t, (s ∩ u).Nonempty) → (s ∩ ⋂₀ ↑t).Nonempty ↔ (¬∃ a ∈ t, s ⊆ aᶜ) → ¬s ⊆ ⋃ x ∈ ↑t, xᶜ

tactic: simp only [not_exists, not_and, ← compl_iInter₂, ← sInter_eq_biInter,
  subset_compl_iff_disjoint_right, not_disjoint_iff_nonempty_inter]
state_before: X : Type u_1
Y : Type u_2
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
s t✝ : Set X
t : Finset (Set X)
x✝ : ∀ u ∈ t, IsOpen u
⊢ (∀ u ∈ t, (s ∩ u).Nonempty) → (s ∩ ⋂₀ ↑t).Nonempty ↔ (¬∃ a ∈ t, s ⊆ aᶜ) → ¬s ⊆ ⋃ x ∈ ↑t, xᶜ
state_after: no goals