Prime powers and factorizations #
This file deals with factorizations of prime powers.
theorem
IsPrimePow.minFac_pow_factorization_eq
{n : ℕ}
(hn : IsPrimePow n)
:
Nat.minFac n ^ ↑(Nat.factorization n) (Nat.minFac n) = n
theorem
isPrimePow_of_minFac_pow_factorization_eq
{n : ℕ}
(h : Nat.minFac n ^ ↑(Nat.factorization n) (Nat.minFac n) = n)
(hn : n ≠ 1)
:
theorem
isPrimePow_iff_minFac_pow_factorization_eq
{n : ℕ}
(hn : n ≠ 1)
:
IsPrimePow n ↔ Nat.minFac n ^ ↑(Nat.factorization n) (Nat.minFac n) = n
theorem
isPrimePow_iff_factorization_eq_single
{n : ℕ}
:
IsPrimePow n ↔ ∃ p k, 0 < k ∧ Nat.factorization n = fun₀ | p => k
theorem
isPrimePow_iff_card_support_factorization_eq_one
{n : ℕ}
:
IsPrimePow n ↔ Finset.card (Nat.factorization n).support = 1
theorem
exists_ord_compl_eq_one_iff_isPrimePow
{n : ℕ}
(hn : n ≠ 1)
:
IsPrimePow n ↔ ∃ p, Nat.Prime p ∧ n / p ^ ↑(Nat.factorization n) p = 1
An equivalent definition for prime powers: n
is a prime power iff there is a unique prime
dividing it.
theorem
Nat.Coprime.isPrimePow_dvd_mul
{n : ℕ}
{a : ℕ}
{b : ℕ}
(hab : Nat.Coprime a b)
(hn : IsPrimePow n)
:
theorem
Nat.mul_divisors_filter_prime_pow
{a : ℕ}
{b : ℕ}
(hab : Nat.Coprime a b)
:
Finset.filter IsPrimePow (Nat.divisors (a * b)) = Finset.filter IsPrimePow (Nat.divisors a ∪ Nat.divisors b)