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FormalConjectures.ErdosProblems.«307»

Erdős Problem 307 #

Reference: erdosproblems.com/307

theorem Erdos307.erdos_307 :
(∃ (P : Finset ) (Q : Finset ), (∀ pP, Nat.Prime p) (∀ qQ, Nat.Prime q) 1 = (∑ pP, (↑p)⁻¹) * qQ, (↑q)⁻¹) sorry

Are there two finite set of primes $P$ and $Q$ such that

$$ 1 = \left( \sum_{p \in P} \frac{1}{p} \right) \left( \sum_{q \in Q} \frac{1}{q} \right) $$ ?

Asked by Barbeau [Ba76].

[Ba76] Barbeau, E. J., Computer challenge corner: Problem 477: A brute force program.

theorem Erdos307.erdos_307_coprime :
(∃ (P : Finset ) (Q : Finset ), (↑P).Pairwise Nat.Coprime (↑Q).Pairwise Nat.Coprime 1 = (∑ pP, (↑p)⁻¹) * qQ, (↑q)⁻¹) sorry

Instead of asking for sets of primes, ask only that all primes in the sets be relatively coprime.