Bourgain–Kakeya conjecture for fat arithmetic progressions
Establish that for T = N^α with 1 < α < 2, after partitioning {N+1,…,2N} into intervals I of length ≍ N T^{−1/2} and forming their associated fat arithmetic progressions I*, any choice of translates t_I ∈ [0,T] satisfies ∫_0^T (∑_I 1_{I* + t_I})^{p/2} ≤ C(ε,α) N^ε ∫_0^T (∑_I 1_{I*})^{p/2} for all p ≥ 1 and ε > 0.
References
Conjecture Fix α ∈ (1,2) and suppose that T = Nα. Divide {N+1, ..., 2N} into intervals I of length ∼ N T{−1/2}. Let I* be as above. There is a constant C(ε, α) so that for every N and every p ≥ 1 and every choice of t_I ∈ [0,T],
∫0T ( ∑_I 1{I* + t_I} ){p/2} ≤ C(ε) Nε ∫0T ( ∑_I 1{I*} ){p/2}.
— Large value estimates in number theory, harmonic analysis, and computer science
(2503.07410 - Guth, 10 Mar 2025) in Section 9 (A barrier related to the Kakeya problem)