# σ0 = ∞, (σ0 to n) + σ1 = σ0 ⊦ # σ1 = ∞ ∧ (⌜n0⌝ < # σ1 → σ1[n0] = (σ0 from n)[n0])
Used simplifier rules: ⊦ # σ0 = ∞ → #(σ0 from n) = ∞; (s)