simp only [subList'] at *
case cons
t : Prop
l : List Prop
ih : ∀ {ps : List Prop} {i j : Nat}, orN ps → ps = subList' l i j → orN l
⊢ ∀ {ps : List Prop} {i j : Nat}, orN ps → ps = subList' (t :: l) i j → orN (t :: l)
case cons
t : Prop
l : List Prop
ih : ∀ {ps : List Prop} {i j : Nat}, orN ps → ps = drop i (take j l) → orN l
⊢ ∀ {ps : List Prop} {i j : Nat}, orN ps → ps = drop i (take j (t :: l)) → orN (t :: l)