OAI/NumberTheory/EgyptianFractions/SmallPrimeDivisors.lean

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3 declarations, 0 contain sorry, 0 declared as axioms

  1. theorem OAI.Problem337.divisor_card_small_primes_bound line 9

    Source documentation

    A number with only small prime factors has few divisors once its logarithm is bounded.

    theorem divisor_card_small_primes_bound (z W : ℝ) {n : ℕ} (hn : n ≠ 0)
        (hz : 0 ≤ z) (hnW : Real.log (n : ℝ) ≤ W)
        (hsmall : ∀ p ∈ n.primeFactors, (p : ℝ) ≤ z) :
        (n.divisors.card : ℝ) ≤ Real.exp (z * Real.log (1 + W / Real.log 2)) := by
    …
  2. theorem OAI.Problem337.truncatedDivisorCount_pointwise_exp_bound line 55

    Source documentation

    Split the factor list at z and combine the small- and large-prime estimates.

    theorem truncatedDivisorCount_pointwise_exp_bound (X z W : ℝ) {n : ℕ} (hn : n ≠ 0)
        (hX : 1 < X) (hz : 1 < z) (hXW : Real.log X ≤ W)
        (hnW : Real.log (n : ℝ) ≤ W) :
        (truncatedDivisorCount X n : ℝ) ≤
          Real.exp (z * Real.log (1 + W / Real.log 2) +
            (1 + Real.log (W / Real.log X)) * Real.log X / Real.log z) := by
    …

    Mentions: OAI.Problem337.truncatedDivisorCount

  3. theorem OAI.Problem337.truncatedDivisorCount_pointwise_log_bound line 116

    Source documentation

    Logarithmic version of the elementary small/large-prime split.

    theorem truncatedDivisorCount_pointwise_log_bound (X z W : ℝ) {n : ℕ} (hn : n ≠ 0)
        (hX : 1 < X) (hz : 1 < z) (hXW : Real.log X ≤ W)
        (hnW : Real.log (n : ℝ) ≤ W) :
        Real.log (truncatedDivisorCount X n : ℝ) ≤
          z * Real.log (1 + W / Real.log 2) +
            (1 + Real.log (W / Real.log X)) * Real.log X / Real.log z := by
    …

    Mentions: OAI.Problem337.truncatedDivisorCount