Erdős problem 47If δ>0\delta>0 and NN is sufficiently large in terms of δ\delta, and A⊆{1,…,N}A\subseteq\{1,\ldots,N\} is such that ∑a∈A1a>δlogN\sum_{a\in A}\frac{1}{a}>\delta \log N then must there exist S⊆AS\subseteq A such that ∑n∈S1n=1\sum_{n\in S}\frac{1}{n}=1?WorkspaceContinue locallyOpen sourceSign in to contributeOpen this exact Problem, source revision, and authority Repository in Workbench. This handoff does not clone, switch, upload, or execute anything.FilesErdős problem 474 retained source recordsCanvaspublic previewSource#47→ResultNone→Checks0