induction Γ using List.induction_with_singleton with
| hnil => simpa using dhyp! multiboxverum!;
| hsingle => simp;
| hcons p Γ h ih =>
  simp_all;
  exact imp_trans! (implyRightAnd! (generalConj'! (by simp)) (imp_trans! (by simp) ih)) collect_multibox_and!;
F : Type u_1
inst✝⁷ : StandardModalLogicalConnective F
inst✝⁶ : DecidableEq F
S : Type u_2
inst✝⁵ : System F S
p q r : F
Γ Δ : List F
𝓢 : S
inst✝⁴ : Classical 𝓢
inst✝³ : System.NegationEquiv 𝓢
inst✝² : Necessitation 𝓢
inst✝¹ inst✝ : HasAxiomK 𝓢
n : ℕ
⊢ 𝓢 ⊢! (□'^[n]Γ).conj' ⟶ □^[n]Γ.conj'
no goals