⊦ prime(n) ↔ 1 < n ∧ (∀ m. m | n → m = 1 ∨ m = n)
1 < m * n, ∀ m0. m0 | m * n → m0 = 1 ∨ m0 = m * n ⊦ m = 1, n = 1
Used terms: m * n