| # x = n0 + n, # x - n < # x ↔ x = firstn(# x - n, x) + restn(# x - n, x) ∧ # x - n < # x ⊦ ∃ y. x = y + lastn(n, x) ∧ # y = n0 |
# x = n0 + n, n ≠ 0 → x = firstn(n0, x) + restn(n0, x) ⊦ ∃ y. x = y + lastn(n, x) ∧ # y = n0
Used simplifier rules: ⊦ m + n - m = n; (s)% ⊦ m < m + n ↔ n ≠ 0; (s)%n0 ≤ n ⊦ n - n0 < m ↔ n < m + n0; (s)%c: ⊦ m + n = n + m; from specification nat-basic%a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic% ⊦ ¬ m + n < m; (s)% ⊦ m ≤ n ↔ ¬ n < m; (ss)