simp only [Nat.succ_add, ih, corec_succ]
case h.succ
α : Type u_1
σ✝ σ : Stream' α
j✝ i j : ℕ
ih : σ (i + j + 1) = corec σ (fun x => x + 1) (j + 1) i
⊢ σ (Nat.succ i + j) = corec σ (fun x => x + 1) j (Nat.succ i)
no goals