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Erdős problem 26

Let A⊂NA\subset\mathbb{N} be infinite. Must there exist some k≥1k\geq 1 such that almost all integers have a divisor of the form a+ka+k for some a∈Aa\in A? The question as posed follows negatively from Davenport–Erdős (1951). The AI result settles Tenenbaum's harder variant, also negatively: there is an infinite AA such that for every k≥1k\geq 1 the set of multiples of A+kA+k has upper density below 0.340.34.

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Exact provenance

Problem row
sha256:f6b8ebc7cc437e125cb703f55148858dd1b5825da5ad06f49ca6bfc85c13bb35
Metadata
sha256:084f6a22c21d64d7b30eb9429a7299f61b037f2141ae98da7d58c2df23f32e94
Observation
sha256:9c8326e865b6017b103af7611c852a06776d81964979b8ab5a1b800cd550dff6
Content
sha256:f7cd51709a2e21c333269085405df775c2888997f3ed9dcd7417a764de500b74
Repository
sha256:a956b84c437202e5a02cc9e036a621bd14a302b34a75758115730bdbb77c52a4
Projection
sha256:a4a96441668a9f8b33afbcb3f696a2639f5fae145f36ddc063d7f67d5fb87ce8
Source commit
36c6d0fef71a3fec84d9dcd5eeca4e22e378f7cb