Efficiency of shading in Kakeya maximal function approaches in R^3

Investigate whether the Wang–Zahl framework can be refined to avoid iterative losses from λ to λ^2 in local density estimates, thereby maintaining a near-linear dependence on λ through rescalings and induction on scale and advancing toward the Kakeya maximal function conjecture in R^3.

Background

Progress toward the Kakeya maximal function in R3 requires controlling shaded tube unions Y(T) with |Y(T)| ≥ λ|T|. Cordoba-type 2D arguments typically yield λ2 density in local prisms, and repeated rescalings cause λ to degrade to λ{2N}, obstructing iteration.

The open problem asks for more efficient implementations (or stronger shading hypotheses) in the Wang–Zahl strategy that prevent such losses, potentially enabling induction-on-scale arguments compatible with Kakeya maximal function bounds.

References

An interesting open problem is whether the arguments in can be performed in a more efficient manner (perhaps with stronger hypotheses about the shadings $Y(T)$) to prevent the losses described above.

A Survey of the Kakeya conjecture, 2000-2025 (2512.09397 - Zahl, 10 Dec 2025) in Subsection “Future directions.”, Section 3