DMS Analysis and Stochastic Analysis Seminar (SASA)

Speaker: Bingyang Hu (Auburn University)

Title: On the curved Trilinear Hilbert transform

Abstract: The goal of this talk is to discuss the Lp boundedness of the trilinear Hilbert transform along the moment curve. More precisely, we show that the operator

is bounded from \(L^{p_1}(\mathbb R) \times L^{p_2}(\mathbb R) \times L^{p_3}(\mathbb R)\) into \(L^r(\mathbb R)\) within the Banach Hölder range \(\frac{1}{p_1}+\frac{1}{p_2}+\frac{1}{p_3}=\frac{1}{r}\) with \(1<p_1, p_3<\infty\), \(1<p_2 \le \infty\) and \(1 \le r <\infty\).
The main difficulty in approaching this problem (compared to the classical approach to the bilinear Hilbert transform) is the lack of absolute summability after we apply the time-frequency discretization (which is known as the LGC-methodology introduced by V. Lie in 2019). To overcome such a difficulty, we develop a new, versatile approach — referred to as Rank II LGC (which is also motived by the study of the non-resonant bilinear Hilbert–Carleson operator by C. Benea, F. Bernicot, V. Lie, and V. Vitturi in 2022), whose control is achieved via the following interdependent elements:

1). a sparse-uniform decomposition of the input functions adapted to an appropriate time-frequency foliation of the phase-space;

2). a structural analysis of suitable maximal "joint Fourier coefficients";

3). a level set analysis with respect to the time-frequency correlation set.

This is a joint work with my postdoc advisor Victor Lie from Purdue.