| 0 < j, 0 < i, ∀ i0, j. i→n(i0) < i→n(i) → 0 < i0 ∧ 0 < j → (fac(i0) ≤ fac(j) ↔ i0 ≤ j) ⊦ fac(i) ≤ fac(j) ↔ i ≤ j |
⊦ 0 < i → fac(i) = i * fac(i - 1)
0 < i, 0 < j, 0 < i, ∀ i0, j. i→n(i0) < i→n(i) → 0 < i0 ∧ 0 < j → (fac(i0) ≤ fac(j) ↔ i0 ≤ j) ⊦ i * fac(i - 1) ≤ fac(j) ↔ i ≤ j
Used terms: i