subst_eqs
case intro
x : ℕ
F : List Formula
δ : List Program
a✝ : Formula
x_notin : x ∉ vocabOfFormula a✝
left✝ : F = [a✝]
right✝ : δ = []
⊢ (∀ x_1 ∈ F, x ∉ vocabOfFormula x_1) ∧ ∀ x_1 ∈ δ, x ∉ vocabOfProgram x_1
case intro.refl.refl
x : ℕ
a✝ : Formula
x_notin : x ∉ vocabOfFormula a✝
⊢ (∀ x_1 ∈ [a✝], x ∉ vocabOfFormula x_1) ∧ ∀ x_1 ∈ [], x ∉ vocabOfProgram x_1