Gagliardo-Nirenberg inequality with Hölder norms
Mengxia Dong
TL;DR
This paper extends the classical Gagliardo-Nirenberg inequality to a unified framework that combines Sobolev and Hölder spaces via the X^p scale. It introduces an interpolation lemma bridging Lebesgue and Hölder norms, and uses it to prove a generalized GN inequality in which Lebesgue norms are replaced by Hölder norms under suitable parameter conditions, namely $\|D^l u\|_{X^q} \le C \|D^k u\|_{X^p}^{\theta} \|u\|_{X^r}^{1-\theta}$ with $\frac{1}{q}-\frac{l}{n} = \theta\left(\frac{1}{p}-\frac{k}{n}\right)+(1-\theta)\left(\frac{1}{r}\right)$ and $l\le k$. The approach recovers and extends known results (Sobolev, Morrey, Kufner-Wannebo, Molchanova-Soudský) as special cases and broadens the admissible parameter range. The outcome provides a flexible analytic tool for PDE regularity theory by enabling interpolation between derivatives and functions in a space that intermixes integrability and Hölder regularity.
Abstract
The classical Gagliardo-Nirenberg inequality, known as an interpolation inequality, involves Lebesgue norms of functions and their derivatives. We established an interpolation lemma to connect Lebesgue and Hölder spaces, thus extending the Gagliardo-Nirenberg inequality. This extension involved substituting arbitrary Sobolev norms with appropriate Hölder norms, allowing for a wider range of applicable parameters in the inequality.
