Strict rearrangement inequalities: nonexpansivity and periodic Gagliardo semi-norms

This paper deals with the behavior of the periodic Gagliardo seminorm under two types of rearrangements, namely under a periodic, and respectively a cylindrical, symmetric decreasing rearrangement. Our two main results are Pólya-Szegó type inequalities for these rearrangements. We also deal with the...

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Bibliographic Details
Authors: Csató, Gyula; Mas Blesa, Albert
Format: Article
Status:Accepted version
Publication date:2025
Country:España
Institution:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repository:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:2445/227054
Online Access:https://hdl.handle.net/2445/227054
Access Level:Open access
Keyword:Equacions en derivades parcials
Desigualtats (Matemàtica)
Partial differential equations
Inequalities (Mathematics)
Description
Summary:This paper deals with the behavior of the periodic Gagliardo seminorm under two types of rearrangements, namely under a periodic, and respectively a cylindrical, symmetric decreasing rearrangement. Our two main results are Pólya-Szegó type inequalities for these rearrangements. We also deal with the cases of equality. Our method uses, among others, some classical nonexpansivity results for rearrangements for which we provide some slight improvements. Our proof is based on the ideas of [Frank and Seiringer, Non-linear ground state representations and sharp Hardy inequalities, J. Funct. Anal., 2008], where a new proof to deal with the cases of equality in the nonexpansivity theorem was given, albeit in a special case involving the rearrangement of only one function.