simp [vocabOfProgram]
case intro.intro.intro.intro.intro.inr.intro.refl.refl.inr.refl
x : ℕ
F : List Formula
α : Program
x_notin : x ∉ vocabOfProgram α
δ' : List Program
h✝ : ¬δ' = []
Fδ'_in_Hα : (F, δ') ∈ H α
IHα : (∀ x_1 ∈ F, x ∉ vocabOfFormula x_1) ∧ ∀ x_1 ∈ δ', x ∉ vocabOfProgram x_1
⊢ x ∉ vocabOfProgram (∗α)
case intro.intro.intro.intro.intro.inr.intro.refl.refl.inr.refl
x : ℕ
F : List Formula
α : Program
x_notin : x ∉ vocabOfProgram α
δ' : List Program
h✝ : ¬δ' = []
Fδ'_in_Hα : (F, δ') ∈ H α
IHα : (∀ x_1 ∈ F, x ∉ vocabOfFormula x_1) ∧ ∀ x_1 ∈ δ', x ∉ vocabOfProgram x_1
⊢ x ∉ vocabOfProgram α