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Kakeya set conjecture in dimensions n ≥ 3

Prove that every Kakeya set in R^n has Minkowski dimension n and Hausdorff dimension n for all n ≥ 3. A Kakeya set is a compact subset of R^n that contains a unit line segment pointing in every direction; the conjecture is resolved in the plane but remains unresolved in higher dimensions.

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Background

The classical Kakeya set conjecture posits full Hausdorff and Minkowski dimension for sets that contain a unit line segment in every direction. While the conjecture is settled in two dimensions, the higher-dimensional case is a central open problem in geometric measure theory and harmonic analysis.

This paper proves weaker, yet significant, structural results: every Kakeya set in R3 has Assouad dimension 3, and under a stability condition on the equality of Hausdorff and packing dimensions, Kakeya sets in R3 have full Hausdorff and packing dimension. These results do not resolve the classical conjecture but advance understanding of the multi-scale structure of Kakeya sets.

References

The Kakeya set conjecture asserts that every Kakeya set in Rn has Minkowski and Hausdorff dimension n. This conjecture is proved in the plane [1, 2], and is open in three and higher dimensions.

The Assouad dimension of Kakeya sets in $\mathbb{R}^3$ (2401.12337 - Wang et al., 22 Jan 2024) in Section 1 (Introduction)