A Stability Result for a Family of Sharp Gagliardo-Nirenberg Inequalities

Abstract: In a paper, E. Carlen and A. Figalli prove a stability estimate - also known as a quantitative inequality - for a sharp Gagliardo-Nirenberg inequality and use this result to solve a Keller-Segal Equation. The Gagliardo-Nirenberg Inequality that Carlen and Figalli prove their stability estimate for is part of a larger family of sharp Gagliardo-Nirenberg inequalities, for which the sharp constants and extremals were identified in some cases by Carrillo and Toscani, and then for the remaining cases by Del Pino and Dolbeault. We prove a stability estimate for the entire family of sharp Gagliardo-Nirenberg inequalities for which Del Pino and Dolbeault calculated the sharp constants and extremals. Establishing stability estimates of inequalities is an active topic. A key piece of our proof is the application of a continuous dimension generalization of the Bianchi-Egnell Stability Estimate proven by the author.