Poincaré inequalities in punctured domains

Elliott H. Lieb, Robert Seiringer, Jakob Yngvason

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15 Scopus citations

Abstract

The classic Poincaré inequality bounds the Lq-norm of a function f in a bounded domain Ω ⊂ ℝn in terms of some Lp-norm of its gradient in Ω. We generalize this in two ways: In the first generalization we remove a set Τ from Ω and concentrate our attention on Λ = Ω \ Τ. This new domain might not even be connected and hence no Poincaré inequality can generally hold for it, or if it does hold it might have a very bad constant. This is so even if the volume of Τ is arbitrarily small. A Poincaré inequality does hold, however, if one makes the additional assumption that f has a finite Lp gradient norm on the whole of Ω, not just on Λ. The important point is that the Poincaré inequality thus obtained bounds the Lq-norm of f in terms of the Lp gradient norm on Λ (not Ω) plus an additional term that goes to zero as the volume of Τ goes to zero. This error term depends on Τ only through its volume. Apart from this additive error term, the constant in the inequality remains that of the 'nice' domain Ω. In the second generalization we are given a vector field A and replace ∇ by ∇ + iA(x) (geometrically, a connection on a U(1) bundle). Unlike the A = 0 case, the infimum of ∥(∇ + iA)f∥p over all f with a given ∥f∥q is in general not zero. This permits an improvement of the inequality by the addition of a term whose sharp value we derive. We describe some open problems that arise from these generalizations.

Original languageEnglish (US)
Pages (from-to)1067-1080
Number of pages14
JournalAnnals of Mathematics
Volume158
Issue number3
DOIs
StatePublished - Nov 2003

All Science Journal Classification (ASJC) codes

  • Statistics and Probability
  • Statistics, Probability and Uncertainty

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    Lieb, E. H., Seiringer, R., & Yngvason, J. (2003). Poincaré inequalities in punctured domains. Annals of Mathematics, 158(3), 1067-1080. https://doi.org/10.4007/annals.2003.158.1067