A surprising formula for Sobolev norms

Haïm Brezis*, Jean van Schaftingen, Po Lam Yung

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    35 Citations (Scopus)

    Abstract

    We establish the equivalence between the Sobolev seminorm k∇ukLp and a quantity obtained when replacing strong Lp by weak Lp in the Gagliardo seminorm |u|Ws,p computed at s = 1. As corollaries we derive alternative estimates in some exceptional cases (involving W1,1) where the “anticipated” fractional Sobolev and Gagliardo–Nirenberg inequalities fail.

    Original languageEnglish
    Article numbere2025254118
    JournalProceedings of the National Academy of Sciences of the United States of America
    Volume118
    Issue number8
    DOIs
    Publication statusPublished - 23 Feb 2021

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