Some Remarks on the Riesz and reverse Riesz transforms on Broken Line

Fuente: arXiv
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Main Author: He, Dangyang
Format: Preprint
Published: 2025
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author He, Dangyang
author_facet He, Dangyang
contents In this note, we study both the Riesz and reverse Riesz transforms on broken line. This model can be described by $(-\infty, -1] \cup [1,\infty)$ equipped with the measure $dμ= |r|^{d_{1}-1}dr$ for $r \le -1$ and $dμ= r^{d_{2}-1}dr$ for $r\ge 1$, where $d_{1}, d_{2} >1$. For the Riesz transform, we show that the range of its $L^{p}$ boundedness depends solely on the smaller dimension, $d_{1} \wedge d_{2}$. Furthermore, we establish a Lorentz type estimate at the endpoint. In our subsequent investigation, we consider the reverse Riesz inequality by rigorously verifying the $L^{p}$ lower bounds for the Riesz transform for almost every $p\in (1,\infty)$. Notably, unlike most previous studies, we do not assume the doubling condition or the Poincaré inequality. Our approach is based on careful estimates of the Riesz kernel and a method known as harmonic annihilation.
format Preprint
id arxiv_https___arxiv_org_abs_2503_14885
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Some Remarks on the Riesz and reverse Riesz transforms on Broken Line
He, Dangyang
Classical Analysis and ODEs
Analysis of PDEs
Functional Analysis
In this note, we study both the Riesz and reverse Riesz transforms on broken line. This model can be described by $(-\infty, -1] \cup [1,\infty)$ equipped with the measure $dμ= |r|^{d_{1}-1}dr$ for $r \le -1$ and $dμ= r^{d_{2}-1}dr$ for $r\ge 1$, where $d_{1}, d_{2} >1$. For the Riesz transform, we show that the range of its $L^{p}$ boundedness depends solely on the smaller dimension, $d_{1} \wedge d_{2}$. Furthermore, we establish a Lorentz type estimate at the endpoint. In our subsequent investigation, we consider the reverse Riesz inequality by rigorously verifying the $L^{p}$ lower bounds for the Riesz transform for almost every $p\in (1,\infty)$. Notably, unlike most previous studies, we do not assume the doubling condition or the Poincaré inequality. Our approach is based on careful estimates of the Riesz kernel and a method known as harmonic annihilation.
title Some Remarks on the Riesz and reverse Riesz transforms on Broken Line
topic Classical Analysis and ODEs
Analysis of PDEs
Functional Analysis
url https://arxiv.org/abs/2503.14885