. apply iff_provable_list_conj.mpr;
  intro p hp; exact h p (by simp only [List.mem_append]; right; simpa);
case mp.d₂
F : Type u_1
inst✝⁴ : LogicalConnective F
inst✝³ : DecidableEq F
S : Type u_2
inst✝² : System F S
𝓢 : S
inst✝¹ : Minimal 𝓢
p q r : F
Γ Δ : List F
inst✝ : System.NegationEquiv 𝓢
h : ∀ p ∈ Γ ++ Δ, 𝓢 ⊢! p
⊢ 𝓢 ⊢! Δ.conj'
no goals