⊦ ⌜m + n⌝ = ⌜m⌝ + ⌜n⌝
m + 1 = nσ[n], # nσ = ∞, stutf(nσ), ∀ m0. n < m0 → nσ[m0] = m + 1 ⊦ m + 1 = 0, ⌜m⌝ + ⌜1⌝ = leninv(nσ)
Used terms: 1, m