⌜0⌝ = leninv(nσ), n < nσ[m], ⌜m⌝ < # nσ, stutf(nσ) ⊦
Used simplifier rules: ⊦ m < n → n ≠ 0; (s)% ⊦ 0 < m ↔ m ≠ 0; (s)% ⊦ 0 ≤ m; (s)