| n ≤ 1 + # x0, ∀ n, y. n ≤ # x0 → x0 + y to n = x0 to n ⊦ (a ' + x0) + y to n = a ' + x0 to n |
n0 +1 ≤ 1 + # x0, ∀ n, y. n ≤ # x0 → x0 + y to n = x0 to n, ∀ x0, a, y. n0 ≤ 1 + # x0 ∧ (∀ n, y. n ≤ # x0 → x0 + y to n = x0 to n) → (a ' + x0) + y to n0 = a ' + x0 to n0 ⊦ (a ' + x0) + y to n0 +1 = a ' + x0 to n0 +1
Used simplifier rules: to-zero-l: ⊦ x to 0 = [];%nat freely generated by 0, +1;;