have : L ⊬! p ⋏ List.conj' Γ ⟶ ⊥ := implyLeft_cons_conj'!.not.mp $ @h (p :: Γ) (by
  rintro q hq;
  simp at hq;
  cases hq with
  | inl h => subst h; simp;
  | inr h => simp; right; exact hΓ q h;
)
case mp
α : Type u_1
inst✝² : DecidableEq α
inst✝¹ : Inhabited α
L : DeductionParameter α
inst✝ : L.Normal
T : Theory α
p : Formula α
h : (L)-Consistent insert p T
Γ : List (Formula α)
hΓ : ∀ q ∈ Γ, q ∈ T
hC : L ⊢! p ⋏ Γ.conj' ⟶ ⊥
⊢ False
case mp
α : Type u_1
inst✝² : DecidableEq α
inst✝¹ : Inhabited α
L : DeductionParameter α
inst✝ : L.Normal
T : Theory α
p : Formula α
h : (L)-Consistent insert p T
Γ : List (Formula α)
hΓ : ∀ q ∈ Γ, q ∈ T
hC : L ⊢! p ⋏ Γ.conj' ⟶ ⊥
this : L ⊬! p ⋏ Γ.conj' ⟶ ⊥
⊢ False