| 1 < i, j * j = i * j0 * j0, gcd(j, j0) = 1, 0 < j0, 0 < j, 0 < i, 0 ≤ j0, ∀ i0, j, j0. i→n(i0) < i→n(i) → 0 < i0 ∧ 0 < j ∧ 0 < j0 ∧ gcd(j, j0) = 1 ∧ j * j = i0 * j0 * j0 → (∃ i1. i0 = i1 * i1) ⊦ prime(i), ∃ i0. i = i0 * i0 |
⊦ 1 < i → (prime(i) ↔ (∀ j. prime(j) ∧ j * j ≤ i → ¬ j | i))
1 < i, 1 < i, j * j = i * j0 * j0, gcd(j, j0) = 1, 0 < j0, 0 < j, 0 < i, 0 ≤ j0, ∀ i0, j, j0. i→n(i0) < i→n(i) → 0 < i0 ∧ 0 < j ∧ 0 < j0 ∧ gcd(j, j0) = 1 ∧ j * j = i0 * j0 * j0 → (∃ i1. i0 = i1 * i1) ⊦ ∀ j. prime(j) ∧ j * j ≤ i → ¬ j | i, ∃ i0. i = i0 * i0
Used terms: i