case or _ _ _ _ ih => exact ih
L : Language
Δ✝¹ Δ₁ Δ₂ Γ✝ : Sequent L
p✝¹ q✝¹ r : SyntacticFormula L
C C' : Set (SyntacticFormula L)
Δ Γ : Sequent L
p q : SyntacticFormula L
ss : C ⊆ C'
Δ✝ : List (SyntacticFormula L)
p✝ q✝ : SyntacticFormula L
a✝ : Derivation (p✝ :: q✝ :: Δ✝)
ih : CutRestricted C a✝ → CutRestricted C' a✝
⊢ CutRestricted C a✝ → CutRestricted C' a✝
no goals