Erdős Problem a Daythe open tracker

Erdős Problem #1146

OPENdatabase updated 2026-01-23

No proof or disproof is known, and it isn't known whether a finite computation could settle it.

What the community database records, not our verdict. erdosproblems.com no longer shows statuses (why).

We say that \(A\subset \mathbb{N}\) is an essential component if \(d_s(A \oplus B)>d_s(B)\) for every \(B\subset \mathbb{N}\) with \(0<d_s(B)<1\) where \(d_s\) is the Schnirelmann density. Here, the sumset is the appropriate one for Schnirelmann density, \(A \oplus B = \{a+b \mid a \in A \cup \{0\}, b \in B \cup \{0\}\}\) (i.e. \((A \cup \{0\}) + (B \cup \{0\})\)). This avoids the trivial case where the sumset misses \(1\) simply because neither \(A\) nor \(B\) contains \(0\).

Is \(B=\{2^m3^n : m,n\geq 0\}\) an essential component? 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."
Statement as formalized in Formal Conjectures (Google DeepMind, Apache-2.0) · their label: research open. The authoritative wording is on erdosproblems.com/1146.
Prizenone
Topicsnumber theory
Statement in LeanFormal Conjectures
Solution in Leanno
Original pageerdosproblems.com/1146
WORKING REPORT BY THIS SITE · JUL 29, 2026

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#1146 remains open; a counterexample must have vanishing simultaneous \(2^m3^n\)-boundary along density-minimizing prefixes, all eventually periodic competitors are excluded, and exact optimization gi

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