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.
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)