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We say that $A\subset \mathbb{N}$ is an essential component if $d_s(A+B)>d_s(B)$ for every $B\subset \mathbb{N}$ with $0<d_s(B)<1$ where $d_s$ is the Schnirelmann density.

Is $B=\{2^m3^n : m,n\geq 0\}$ an essential component?
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In [Ru99] Ruzsa states "The simplest set with a chance to be an essential component is the collection of numbers in the form $2^m3^n$ and Erdős often asked whether it is an essential component or not; I do not even have a plausible guess."

See also [37].

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This page was last edited 23 January 2026.

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T. F. Bloom, Erdős Problem #1146, https://www.erdosproblems.com/1146, accessed 2026-03-01