English
For any a,b, radical(a b) divides radical(a) radical(b).
Русский
Для любых a,b, radical(ab) делит radical(a) radical(b).
LaTeX
$$$\operatorname{radical}(a b) \mid \operatorname{radical}(a) \cdot \operatorname{radical}(b)$$$
Lean4
theorem radical_mul_dvd : radical (a * b) ∣ radical a * radical b := by
classical
obtain rfl | ha := eq_or_ne a 0
· simp
obtain rfl | hb := eq_or_ne b 0
· simp
nontriviality M
simp [radical_dvd_iff_primeFactors_subset, primeFactors_mul_eq_union, primeFactors_mul_eq_union ha hb,
primeFactors_radical]