max∞(λ n0. ⌜n0⌝ < # nσ ∧ nσ[n0] = n) = ∞, leninv(nσ) = ⌜n0⌝ , stutf(nσ), n < n0 ⊦ n0 = 0, ⌜∞.n⌝ < # nσ