In the present paper, we prove that the augmented Lagrangian method converges to KKT points under the quasinormality constraint qualification, which is associated with the external penalty theory. An interesting consequence is that the Lagrange multipliers estimates computed by the method remain bounded in the presence of the quasinormality condition. In order to establish a more general convergence result, a new sequential optimality condition for smooth constrained optimization, called PAKKT, is defined. The new condition takes into account the sign of the dual sequence, constituting an adequate sequential counterpart to the (enhanced) Fritz-John necessary optimality conditions proposed by Hestenes, and later extensively treated by Bertsekas. PAKKT points are substantially better than points obtained by the classical Approximate KKT (AKKT) condition, which has been used to establish theoretical convergence results for several methods. In particular, we present a simple problem with complementarity constraints such that all its feasible points are AKKT, while only the solutions and a pathological point are PAKKT. This shows the efficiency of the methods that reach PAKKT points, particularly the augmented Lagrangian algorithm, in such problems. We also provided the appropriate strict constraint qualification associated with the PAKKT sequential optimality condition, called PAKKT-regular, and we prove that it is strictly weaker than both quasinormality and cone continuity property. PAKKT-regular connects both branches of these independent constraint qualifications, generalizing all previous theoretical convergence results for the augmented Lagrangian method in the literature.where f : R n → R and X is the feasible set composed of equality and inequality constraints of the form X = {x | h(x) = 0, g(x) ≤ 0}, * This work has been partially supported by CEPID-CeMEAI (FAPESP 2013/07375-0), FAPESP (Grant 2013/05475-7) and CNPq (Grant 303013/2013-3).

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En esta tesis estudiamos la posibilidad de extender el método Lagrangiano Aumentado clásico de optimización escalar, para resolver problemas con objetivos múltiples. El método Lagrangiano Aumentado es una técnica popular para resolver problemas de optimización con restricciones. Consideramos dos posibles extensiones: - mediate el uso de escalarizaciones. Basados en el trabajo consideramos el uso de funciones débilmente crecientes para analizar la convergencia global de un método Lagrangiano Aumentado para resolver el problema multiobjetivo con restricciones de igualdad y de desigualdad. - mediante el uso de una función Lagrangiana Aumentada vectorial. En este caso el subproblema en el método Lagrangiano Aumentado tiene la particularidad de ser vectorial y planetamos su resolución mediante el uso de un método del tipo gradiente proyectado no monótono. En las extensiones que presentamos en la tesis se analizan las hipótesis más débiles bajo las cuales es posible demostrar convergencia a un punto estacionario del problema multiobjetivo.