exact ⟨isProper_ofDerivation ⟨b, by simpa[CutFree] using H⟩, by simp[List.subset_def]; intro x hx; simp[hx]⟩
μ : Type ?u.910235
L : Language
inst✝⁶ : (k : ℕ) → DecidableEq (L.Func k)
inst✝⁵ : (k : ℕ) → DecidableEq (L.Rel k)
inst✝⁴ : (k : ℕ) → Primcodable (L.Func k)
inst✝³ : (k : ℕ) → Primcodable (L.Rel k)
inst✝² : UniformlyPrimcodable L.Func
inst✝¹ : UniformlyPrimcodable L.Rel
inst✝ : Primcodable μ
Γ : List (SyntacticFormula L)
p q : SyntacticFormula L
b : Derivation (p :: q :: Γ)
H : CutFree b.or
⊢ (ofDerivation ⟨b, ⋯⟩).isProper = true ∧ Γ ⊆ p :: q :: p ⋎ q :: Γ
no goals