Generalize the trilinear Fourier restriction approach to cinematic Furstenberg sets

Determine whether the trilinear Fourier restriction approach used for circular Furstenberg sets can be generalized to cinematic (u, v)-Furstenberg sets, including whether such a generalization is possible using variable-coefficient trilinear Fourier restriction.

Background

The paper proves incidence bounds and dimension estimates for circular and sine-wave Furstenberg sets, and also obtains certain bounds for the broader class of cinematic Furstenberg sets. The proof of one circular bound uses a trilinear Fourier restriction theorem specialized to the cone, whereas the cinematic-curve arguments developed later rely on variable-coefficient local smoothing and do not establish an analogous trilinear estimate.

The authors observe that variable-coefficient trilinear Fourier restriction results might provide a route to such an extension, but explicitly state that they have not carried it out and leave its feasibility unresolved. This is a concrete methodological open question concerning whether the stronger trilinear approach can yield corresponding results for cinematic families.

References

It may be possible to generalise the trilinear Fourier restriction approach to cinematic (u, v)-Furstenberg sets, using e.g. variable coefficient trilinear Fourier restriction [32, Theorem 1.16], but we have not attempted to carry this out, so we leave this as an open question whether such a generalisation is possible.

Incidence bounds related to circular Furstenberg sets  (2502.10686 - Green et al., 15 Feb 2025) in Section 1.1, page 4