| i0 + i < 0, 0 < i, 0 < i0 ⊦ |
0 < i0, 0 < i1 +1, i0 + i1 +1 < 0, ∀ i0. ¬(i0 + i1 < 0 ∧ 0 < i1 ∧ 0 < i0) ⊦
Used simplifier rules: sub-pred: ⊦ i -1 = i - 1;%sub-add-01: ⊦ i + (j - i0) = i + j - i0;%sub-ls: ⊦ i - j < i0 ↔ i < j + i0;%lsone: ⊦ i < 1 ↔ i ≤ 0;%le-def: ⊦ i ≤ j ↔ ¬ j < i;%sub-ls-01: ⊦ i < j - i0 ↔ i + i0 < j;%numlsf-01: ⊦ (* i) < j ∧ 0 < i → 0 ≤ j ∧ 0 < j;%forward-le-05: ⊦ i < j ∧ 0 ≤ i → 0 < j;%int generated by 0, +1, -1;;%add-a: ⊦ i + j + i0 = (i + j) + i0; from specification int-basic2%add-c: ⊦ i + j = j + i; from specification int-basic2%forward-pos: ⊦ i < j ∧ 0 < i → 0 < j ∧ 1 < j; (forward) from specification int-basic1% ⊦ i < j → ¬ j < i; (s)% ⊦ 0 < i ∧ 0 < j → 0 < i + j; (s)% ⊦ 0 + i = i; (s)