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Bibliographic Details
Main Author: Honoré, Igor
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2504.06657
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author Honoré, Igor
author_facet Honoré, Igor
contents In this article, we develop a new method, based on a time decomposition of a Cauchy problem elaborated in [6], to retrieve the well-known $L^\infty ([0,T],L^2(\mathbb{R}^d,\mathbb{R}^d))$ control of the solution of the incompressible Navier-Stokes equation in $\mathbb{R}^d$. We precisely explain how the Pythagorean theorem in $L^2(\mathbb{R}^d,\mathbb{R}^d)$ allows to get the proper energy estimate; however such an argument does not work anymore in $L^p(\mathbb{R}^d,\mathbb{R}^d)$, $p \neq 2$. We also deduce, by similar arguments, an already known $L^\infty ([0,T],L^1(\mathbb{R}^3,\mathbb{R}^3))$ control of vorticity for $d=3$.
format Preprint
id arxiv_https___arxiv_org_abs_2504_06657
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle When Pythagoras meets Navier-Stokes
Honoré, Igor
Analysis of PDEs
In this article, we develop a new method, based on a time decomposition of a Cauchy problem elaborated in [6], to retrieve the well-known $L^\infty ([0,T],L^2(\mathbb{R}^d,\mathbb{R}^d))$ control of the solution of the incompressible Navier-Stokes equation in $\mathbb{R}^d$. We precisely explain how the Pythagorean theorem in $L^2(\mathbb{R}^d,\mathbb{R}^d)$ allows to get the proper energy estimate; however such an argument does not work anymore in $L^p(\mathbb{R}^d,\mathbb{R}^d)$, $p \neq 2$. We also deduce, by similar arguments, an already known $L^\infty ([0,T],L^1(\mathbb{R}^3,\mathbb{R}^3))$ control of vorticity for $d=3$.
title When Pythagoras meets Navier-Stokes
topic Analysis of PDEs
url https://arxiv.org/abs/2504.06657