Young measures and relaxation of functionals for integrands $f(x,u(x),u'(x))$

Abstract

In this paper, we examine the question of optimality conditions in terms of Young's measures for a relaxed problem associated to a one-dimensional nonconvex problem of the calculus of variations of the type $\inf \int_a^b f(x,u(x),u' (x))dx.$ Once these conditions are established, we set sufficient conditions for the existence of solutions of the nonconvex problem.