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