Dacorogna, BernardCroce, Gisella2005-03-162005-03-162005-03-16200410.5075/epfl-thesis-3010https://infoscience.epfl.ch/handle/20.500.14299/212285urn:nbn:ch:bel-epfl-thesis3010-5The principal subject of this thesis is the study of some Dirichlet problems related to differential inclusions of first and second order. We have studied the two following problems : where E ⊂ R2×2 is a compact isotropic set and where We show some existence theorems of W1,∞ and W2,∞ solutions respectively. Moreover we have studied a minimization problem : the computation of α(p, q, r) defined byfrthesis::doctoral thesis