Kakeya type problems

A Kakeya set in d-dimensional Euclidean space is a (compact) set which contains a unit line segment in all directions. The Kakeya conjecture is that the Hausdorff dimension of such a Kakeya set must be d. This conjecture is open for all d>3. A rough heuristic for this conjecture is that a line segment is 1-dimensional and the set of directions is of dimension d-1 and, since the set of directions is suitably transverse, the dimensions should add. This type of heuristic applies much more generally. I have worked on the Kakeya problem in various contexts (often avoiding the problem itself!). Some of my work on Kakeya type problems includes variants such as the Furstenberg set problem, (d,k)-sets, and the Kakeya problem in vector spaces over finite fields: The Kakeya problem is related to Fourier restriction, another problem I have worked a bit on:



Two Kakeya sets in the plane. Are you convinced? Try to find a direction which is not witnessed!

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