| (i→n(i1) + 1) + i→n(j) = i→n((i1 + 1) + j), 0 ≤ j, 0 ≤ i1, ∀ j0. 0 ≤ j0 → (i→n(i1) + 1) + i→n(j0) = i→n((i1 + 1) + j0) ⊦ i→n(i1) + i→n(j) = i→n(j + i1) |
⊦ 0 < i → i→n(i) = i→n(i - 1) + 1
Used simplifier rules: numsub: ⊦ (* i) + i0 - (* j) = (i - j) + i0; from specification int-abs%add-zero-rev: ⊦ 0 + i = i; from specification int-basic2%add-a: ⊦ i + j + i0 = (i + j) + i0; from specification int-basic2%add-c: ⊦ i + j = j + i; from specification int-basic2%eq-01: ⊦ m + n = m + n0 ↔ n = n0; from specification nat-basic2%a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic2%c: ⊦ m + n = n + m; from specification nat-basic2%numls-02: ⊦ (* j) < i0 + (* j0) ↔ j - j0 < i0; from specification int-abs%mone-06: ⊦ ~1 < i ↔ 0 ≤ i; from specification int-abs%lels-01: ⊦ ¬ i ≤ j ↔ j < i; from specification int-abs%zero-gs: ⊦ 0 ≤ i ∧ 0 ≤ j → ¬ i + j < 0; from specification int-abs Used terms: (i1 + 1) + j