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Main Author: Maor, Cy
Format: Preprint
Published: 2018
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Online Access:https://arxiv.org/abs/1802.03066
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author Maor, Cy
author_facet Maor, Cy
contents Verifying lower-semicontinuity of integral functionals in the weak topology of Sobolev spaces is a central theme in the calculus of variations. For integral functionals with $p$-growth, quasiconvexity is a necessary condition for weak lower-semicontinuity in $W^{1,p}$, but is only sufficient if some additional conditions are met.The standard functional showing the necessity of additional conditions is $f\mapsto \int_Ω\det \nabla f$, which fails to be weakly lower-semicontinuous. However, the common examples showing this failure are non-injective and have a lot of shear. The aim of this short note is to point out that a known sequence of conformal diffeomorphisms of the $d$-dimensional unit ball that converges weakly to a constant in $W^{1,d}$, exemplifies the weak discontinuity of this functional even when restricting a space to functions which are "as nice as possible".
format Preprint
id arxiv_https___arxiv_org_abs_1802_03066
institution arXiv
publishDate 2018
record_format arxiv
spellingShingle A simple example of the weak discontinuity of $f\mapsto \int \det \nabla f$
Maor, Cy
Analysis of PDEs
49J45
Verifying lower-semicontinuity of integral functionals in the weak topology of Sobolev spaces is a central theme in the calculus of variations. For integral functionals with $p$-growth, quasiconvexity is a necessary condition for weak lower-semicontinuity in $W^{1,p}$, but is only sufficient if some additional conditions are met.The standard functional showing the necessity of additional conditions is $f\mapsto \int_Ω\det \nabla f$, which fails to be weakly lower-semicontinuous. However, the common examples showing this failure are non-injective and have a lot of shear. The aim of this short note is to point out that a known sequence of conformal diffeomorphisms of the $d$-dimensional unit ball that converges weakly to a constant in $W^{1,d}$, exemplifies the weak discontinuity of this functional even when restricting a space to functions which are "as nice as possible".
title A simple example of the weak discontinuity of $f\mapsto \int \det \nabla f$
topic Analysis of PDEs
49J45
url https://arxiv.org/abs/1802.03066