English
Prime p iff p ≥ 2 and every divisor m < p, with m | p, satisfies m = 1.
Русский
Простое число p эквивалентно p ≥ 2 и каждому делителю m < p, делящему p, выполняется m = 1.
LaTeX
$$$\\\\mathrm{Prime}(p) \\\\iff 2 \\\\le p \\\\land \\\\forall m < p, \\\\; m \\\\mid p \\\\rightarrow m = 1$$$
Lean4
theorem prime_def_lt {p : ℕ} : Prime p ↔ 2 ≤ p ∧ ∀ m < p, m ∣ p → m = 1 :=
prime_def.trans <|
and_congr_right fun p2 =>
forall_congr' fun _ =>
⟨fun h l d => (h d).resolve_right (ne_of_lt l), fun h d =>
(le_of_dvd (le_of_succ_le p2) d).lt_or_eq_dec.imp_left fun l => h l d⟩