Abstract
Let be the distance from a compact set in the space of matrices. This note determines the set of zeros of the polyconvex hull of where . It is shown that the set-valued map is constant on the intervals where , while at the set generally jumps down discontinuously. The values , , at the beginnings of intervals of constancy are characterized as -polyconvex hulls of to be defined below, where is the convex hull and the standard polyconvex hull. As an illustration, are evaluated for all if , and for arbitrary if and/or . In the remaining cases only bounds are obtained.
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Published by Heldermann Verlag, 2007. Rights now held by Banach Press LLC.
