The board / graph theory / #1033
Erdős Problem #1033
OPENdatabase updated 2025-12-12
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).
Let \(h(n)\) be such that every graph on \(n\) vertices with \(>n^2/4\) many edges contains a triangle whose vertices have degrees summing to at least \(h(n)\). Estimate \(h(n)\). In particular, is it true that \[h(n)\geq (2(\sqrt{3}-1)-o(1))n?\] A conjecture of Bollobás and Erdős. The answer is no. A blow-up of the butterfly graph, posted on the [Erdős problems forum](https://www.erdosproblems.com/forum/thread/1033) in June and July 2026 and written up in [this note](https://woutercvb.github.io/Erdos1033_smalloptimization.pdf), gives arbitrarily large graphs with more than \(n^2/4\) edges in which every triangle has degree sum at most \(1.464n\), which is less than \(2(\sqrt{3}-1)n\). Estimating the optimal value of \(h(n)\) is still open.
Statement as formalized in Formal Conjectures (Google DeepMind, Apache-2.0) · their label: research solved · 3 further variants / known partial results in the Lean file. The authoritative wording is on erdosproblems.com/1033.Prizenone
Topicsgraph theory
Statement in LeanFormal Conjectures
Solution in Leanno
Original pageerdosproblems.com/1033
Attempts
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Exhaustive computation gives h(3..10) = 6,8,9,10,12,13,14,16 with explicit certificates and an independent labeled cross-check through n=7; the asymptotic constant remains open.
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