Erdős Problem #224
PROVED LEANdatabase updated 2026-01-14
The statement as posed is true, and a proof exists. A solution has also been checked by machine, in Lean.
What the community database records, not our verdict. erdosproblems.com no longer shows statuses (why).
The angle \(yxz\) is obtuse.
If \(A\subseteq \mathbb{R}^d\) is any set of \(2^d+1\) points then some three points in \(A\) determine an obtuse angle. The general case was proved by Danzer and Gr\"{u}nbaum [DaGr62].
Statement as formalized in Formal Conjectures (Google DeepMind, Apache-2.0) · their label: research solved. The authoritative wording is on erdosproblems.com/224.Prizenone
Topicsgeometry
Statement in LeanFormal Conjectures
Solution in Leanyes
Original pageerdosproblems.com/224
Attempts
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