| ⊦ 0 ≤ i ∧ 0 ≤ j → ((i * (i + 1)) / 2 < ((j + 1) * (j + 2)) / 2 ↔ i < j + 1) |
0 ≤ i, 0 ≤ j ⊦ (i * (i + 1)) / 2 < ((j + 1) * (j + 2)) / 2 ↔ i ≤ j
Used simplifier rules: forward-le-01: ⊦ i ≤ j ∧ 0 ≤ i → 0 ≤ j; (forward) from specification int-abs%add-c: ⊦ i + j = j + i; from specification int-basic2%add-a: ⊦ i + j + i0 = (i + j) + i0; from specification int-basic2%succ-02: ⊦ i < j + 1 ↔ i ≤ j; from specification int-abs