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Falconer Distance Conjecture


The Falconer distance conjecture asserts that a compact set E subset= R^d with Hausdorff dimension greater than d/2 has a distance set Delta(E)={||x-y||:x,y in E} of positive Lebesgue measure, where d>=2 and ||·|| is the Euclidean norm (Iosevich and Yavicoli 2026).

Iosevich and Yavicoli (2026) proved that some absolute constant eta_0>0 satisfies dim_HDelta(E)>=4/5+eta_0 for every analytic set E subset= R^2 with dim_HE>1. This is a Hausdorff dimension bound rather than a proof of the conjecture.

OpenAI (2026) announced a proof in every integer dimension d>=2 for compact sets E subset= R^d with dim_HE>d/2. The claimed conclusion is positive Lebesgue measure of the Euclidean distance set, rather than only a lower Hausdorff dimension bound. The strict threshold is retained and no endpoint or pinned-distance conclusion is asserted here. The release proofs have not been independently verified here.

Cheng et al. (2026) report a quantitative planar result. Let E subset R^2 be compact, with generalized diameter D>0, supporting a probability measure mu such that

 mu(B(x,r))<=A(r/D)^(1+epsilon)

for every x in R^2 and 0<r<=D, where A>=1, 0<epsilon<1, and B(x,r) is an open disk. They claim

 |Delta(E)|>=c_(epsilon,p)DA^(-p)

for every fixed p>1/epsilon, with c_(epsilon,p)>0 depending only on epsilon,p and |Delta(E)| denoting Lebesgue measure. In particular, their result would give positive Lebesgue measure whenever dim_HE>1. It does not assert the endpoint p=1/epsilon, a pinned-distance conclusion, or sharp constants. The authors develop the OpenAI multiscale approach and report AI assistance with local mathematical reasoning (Cheng et al. 2026). Their claimed proof has not been independently verified here.


See also

Distance Set, Hausdorff Dimension, Lebesgue Measure

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References

Cheng, G.; Fang, X.; Li, M.; Qu, H.; and Xiao, C. "A Quantitative Form of the Planar Falconer Distance Theorem." 15 Oct 2026. https://arxiv.org/abs/2610.22222.Iosevich, A. and Yavicoli, A. "Improved Dimension Bounds for Falconer's Distance Problem in the Plane." 4 Oct 2026. https://arxiv.org/abs/2610.05500.OpenAI. "The Falconer Distance Conjecture in All Dimensions." Sep. 23, 2026. https://github.com/openai/math/blob/adc7f1241b42e322a6451854ab7e4b4c146bf78a/preprints/The-Falconer-distance-conjecture-in-all-dimensions-September-23-2026/paper.pdf.

Cite this as:

Weisstein, Eric W. "Falconer Distance Conjecture." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/FalconerDistanceConjecture.html

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