English
Let a,b > 0. The prime factors of gcd(a,b) are exactly the intersection of the prime factors of a and b.
Русский
Пусть a,b > 0. Простые делители НОД(a,b) равны пересечению простых делителей a и b.
LaTeX
$$$ (a \\neq 0) \\land (b \\neq 0) \\Rightarrow (a \\gcd b).primeFactors = a.primeFactors \\cap b.primeFactors $$$
Lean4
theorem primeFactors_gcd (ha : a ≠ 0) (hb : b ≠ 0) : (a.gcd b).primeFactors = a.primeFactors ∩ b.primeFactors := by ext;
simp [dvd_gcd_iff, ha, hb, gcd_ne_zero_left ha]; aesop