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Research notes on every problem, and a library of the papers behind them. Built from the open erdos repository.

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Claim. Theorem 7.3 of Cheuk Fung Lau, On the number of prime factors of consecutive integers, arXiv:2604.15042, carded at Lau 2026, in Section 7, titled by the paper as the conditional falsity of Erdős Problem 679. It assumes the paper's Conjecture 8: for some C0≥1C_0\ge1 and some dd with 1≤d<C01\le d<C_0, every interval (x−(log⁡(x/2))d,x](x-(\log(x/2))^d,x] with xx large contains an integer mm with ω(m)≥C0log⁡log⁡m/log⁡log⁡log⁡m\omega(m)\ge C_0\log\log m/\log\log\log m. Under that assumption there is δ>0\delta>0 such that every sufficiently large nn has some large k<nk<n with

ω(n−k)>(1+δ)log⁡klog⁡log⁡k.\omega(n-k)>(1+\delta)\frac{\log k}{\log\log k}.

So, under the hypothesis only, the first question of Problem 679 has the answer no for every ϵ<δ\epsilon<\delta: only finitely many nn have ω(n−k)<(1+ϵ)log⁡k/log⁡log⁡k\omega(n-k)<(1+\epsilon)\log k/\log\log k for all large k<nk<n. The proof applies the conjecture at x=nx=n and compares $C_0\log\log(n-k)/\log\log\log (n-k)$ with log⁡k/log⁡log⁡k\log k/\log\log k through k≤(log⁡(n/2))dk\le(\log(n/2))^d, which gives the bound with any δ<C0/d−1\delta<C_0/d-1. The claim is conditional: Conjecture 8 is unproven, so this page derives nothing for the problem's standing. Section 7 is unchanged in the paper's second version (2026-06-24). The paper's unconditional Theorem 1.3, that for some CC infinitely many nn have ω(n−k)≤Ω(n−k)≤Clog⁡k\omega(n-k)\le\Omega(n-k)\le C\log k for all 1<k<n1<k<n, settles no instance of the problem and is progress, not a claim; its Conjecture 6, that the Clog⁡kC\log k bound is sharp up to a constant, which would also give a negative answer, is only a conjecture.

Depends on. Nothing in this wiki.

Standing. Claimed, conditional. No refereed version was found; the site's remarks (page last edited 17 April 2026) record Theorem 1.3 and the conjecture, and the site labels the problem OPEN.