Bi-Sobolev Solutions to the Prescribed Jacobian Inequality in the Plane with $L^p$ Data

Abstract

We construct planar bi-Sobolev mappings whose local volume distortion is bounded from below by a given function $f\in L^p$ with $p>1$, i.e. bi-Sobolev solutions for the prescribed Jacobian inequality in the plane for right-hand sides $f\in L^p$. More precisely, for any $1<q<(p+1)/2$ we construct a solution which belongs to $W^{1,q}$ and which preserves the boundary pointwise. For bounded right-hand sides $f\in L^{\infty }$, we provide bi-Lipschitz solutions. The basic building block of our construction are Lipschitz maps which stretch a given compact subset of the unit square by a given factor while preserving the boundary. The construction of these stretching maps relies on a slight strengthening of the covering result of Alberti, Csörnyei, and Preiss for measurable planar sets in the case of compact sets.

arXiv comment37 pages. Changes to previous version: Added the case of right-hand sides in $L^p$ for $1<p<\infty$, moved the details on nonlinear elasticity to future work