| ⊦ m0 ≤ m ∧ m ≤ n → (m * (m + 1)) / 2 + m0 < ((n + 1) * (n + 2)) / 2 |
⊦ ((m + 1) * (m + 2)) / 2 < ((n + 1) * (n + 2)) / 2 ↔ m < n
((n + 1) * (n + 2)) / 2 < ((m + 1) * (m + 2)) / 2 ↔ n < m ⊦ m0 ≤ m ∧ m ≤ n → (m * (m + 1)) / 2 + m0 < ((n + 1) * (n + 2)) / 2
Used terms: n, m