On general vector quasi-optimization problems

Vector general quasi-optimization problems are formulated and some sufficient conditions on the existence of solutions for these problems are shown. These concern the existence of solutions, the stability and the structure of solution set of general vector problems. As special case, we obtain results on the existence of solutions of vector quasi-optimization problem. Some relationships between these problems and others, as vector quasi-equilibrium problems, quasi-variational inequalities, complementarity problems, . . ., are shown. From these we extend some well-known results obtained by Blum and Oettli, Park, Chan and Pang, Parida and Sen, Browder and Minty, Fan, etc.