Prime powers and factorizations #
This file deals with factorizations of prime powers.
theorem
isPrimePow_of_minFac_pow_factorization_eq
{n : ℕ}
(h : n.minFac ^ n.factorization n.minFac = n)
(hn : n ≠ 1)
:
theorem
isPrimePow_iff_minFac_pow_factorization_eq
{n : ℕ}
(hn : n ≠ 1)
:
IsPrimePow n ↔ n.minFac ^ n.factorization n.minFac = n
theorem
isPrimePow_iff_factorization_eq_single
{n : ℕ}
:
IsPrimePow n ↔ ∃ (p : ℕ) (k : ℕ), 0 < k ∧ n.factorization = Finsupp.single p k
An equivalent definition for prime powers: n
is a prime power iff there is a unique prime
dividing it.
theorem
Nat.mul_divisors_filter_prime_pow
{a : ℕ}
{b : ℕ}
(hab : a.Coprime b)
:
Finset.filter IsPrimePow (a * b).divisors = Finset.filter IsPrimePow (a.divisors ∪ b.divisors)