polyconvex envelope; rank one convex envelope; lower semicontinuous functional; quasiconvex functional; coercive integral functional; radially symmetric function of Kohn-Strang type
We study polyconvex envelopes of a class of functions related to the function of Kohn and Strang introduced in . We present an example of a function of this class for which the polyconvex envelope may be computed explicitly and we also point out some general features of the problem.
 B. Dacarogna: Direct Methods in the Calculus of Variations
. Springer-Verlag, New-York 1989. MR 0990890
 B. Dacarogna, H. Koshigoe: On the different notions of convexity for rationally invariant functions. preprint.
 R. Kohn, G. Strang: Optimal design and relaxation of variational problems I, II and III
. Comm. Pure Appl. Math. 39 (1986), 113–137, 139–182, 353–377. DOI 10.1002/cpa.3160390305
| MR 0820342