simp_all
case h₂
Worlds : Finset (Finset Formula)
MG : ModelGraph Worlds
β : Program
Y : { x // x ∈ Worlds }
m : ℕ
innerIH :
  ∀ (X : { x // x ∈ Worlds }) (φ : Formula),
    (⌈∗β⌉φ) ∈ ↑X →
      (∃ ys, X = ys.head ∧ Y = ys.last ∧ ∀ (i : Fin m), relate (↑MG) β (ys.get i.castSucc) (ys.get i.succ)) → φ ∈ ↑Y
X : { x // x ∈ Worlds }
φ : Formula
boxP_in_X : (⌈∗β⌉φ) ∈ ↑X
YS : Vector { x // x ∈ Worlds } (m + 1).succ
X_def : X = YS.head
Y_def : Y = YS.last
relSteps : ∀ (i : Fin (m + 1)), relate (↑MG) β (YS.get i.castSucc) (YS.get i.succ)
Z : { x // x ∈ Worlds } := YS.get 1
X_β_Z : relate (↑MG) β X Z
ℓ : TP (∗β)
mysat : ∀ (x : Formula), (x ∈ F (∗β) ℓ ∨ ∃ a ∈ P (∗β) ℓ, (⌈⌈a⌉⌉φ) = x) → x ∈ ↑X
TP_eq : TP (∗β) = TP β
X_ConF :
  evaluate (↑MG) X
    (Con
      (F β fun x =>
        match x with
        | ⟨f, f_in⟩ => ℓ ⟨f, ⋯⟩))
δ : List Program
δ_in_P :
  δ ∈
    P β fun x =>
      match x with
      | ⟨f, f_in⟩ => ℓ ⟨f, ⋯⟩
X_δ_Z : relateSeq (↑MG) δ X Z
δ_notEmpty : ¬δ = []
⊢ (δ != []) = true
no goals