Szemerédi-Trotter bounds for tubes and applications
Ciprian Demeter, Hong Wang
TL;DR
This work establishes sharp Szemerédi–Trotter type bounds for incidences between planar tubes under packing constraints and translates these bounds into Fourier-analytic estimates for fractal measures supported on planar curves. The authors blend uniform Katz–Tao sets, probabilistic uniformization, Furstenberg-set techniques, and multi-scale decompositions (including two-ends and high–low analyses) to derive a robust tube-incidence bound: for $s\in(0,\tfrac12]$ and appropriate $\delta$, $|\mathcal{P}_r(\mathcal{T})| \lesssim_\upsilon \delta^{-\upsilon}\frac{|\mathcal{T}|^2}{r^3}$ for $1\le r\lesssim \delta^{-s}$. Consequences include refined $L^6$ bounds on the Fourier transform of fractal measures supported on planar curves, improving exponents in the fractal restriction context. The approach advances incidence geometry with packing assumptions and leverages Furstenberg-type bounds to connect geometric configuration to harmonic-analytic estimates, yielding both sharp incidence results and applications to fractal Fourier decay. The methods—probabilistic uniformization, two-ends reductions, and induction on scales—offer a flexible framework for related geometric-probination problems and their Fourier-analytic consequences.
Abstract
We prove sharp estimates for incidences involving planar tubes that satisfy packing conditions. We apply them to improve the estimates for the Fourier transform of fractal measures supported on planar curves.
