| i < 0 ⊦ i = j, 0 = abs(j) + i ↔ 0 = i + j |
Used simplifier rules: abs-08: ⊦ i < 0 → abs(i) = ~ i;%Minus-def: ⊦ ~ i = 0 - i;%sub-zero: ⊦ i + (0 - i0) = i - i0;%sub-eq: ⊦ i - j = i0 ↔ i = i0 + j;%Abs-pos: ⊦ ¬ j < 0 → abs(j) = j;%add-c: ⊦ i + j = j + i; from specification int-basic2%add-a: ⊦ i + j + i0 = (i + j) + i0; from specification int-basic2%add-zero-rev: ⊦ 0 + i = i; from specification int-basic2%zero: ⊦ i < 0 ∧ j < 0 → i + j ≠ 0; from specification int-basic2 Used formulas: j < 0