2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/68168We study a special class of non-convex functions which appear in nonlinear elasticity; and we prove that they have well-defined Legandre transforms. Several examples are given, and an application to a nonlinear eigenvalue problemOptimization and ControlAnalysis of PDEs49N15, 74B20text