| # nσ = ⌜n1⌝ + ⌜1⌝ , stutf(nσ), ∀ n. ∃ n0. n < n0 ∧ (∃ m. ¬ n1 < m ∧ nσ[m] = n0 - 1), ∃ n0. nσ[n1] + 1 < n0 ∧ (∃ m. ¬ n1 < m ∧ nσ[m] = n0 - 1) ⊦ |
# nσ = ⌜n1⌝ + ⌜1⌝ , nσ[m] = n - 1, nσ[n1] + 1 < n, stutf(nσ), m ≤ n1, ∀ n. ∃ n0. n < n0 ∧ (∃ m. ¬ n1 < m ∧ nσ[m] = n0 - 1) ⊦
Used simplifier rules: ⊦ m < n → n ≠ 0; (s)%f: ⊦ m < n → n ≠ 0; (forward) from specification nat-basic% ⊦ m < n ↔ ¬ n ≤ m; (ss)