Résumé en anglais

This paper proposes new concepts and new results which could lead to a more realistic preference modeling than in classical decision theory. Sections 1–3 present four fundamental situations of preferences, their combinations and the concept of relational system of preferences. In §4, a particular case of relational system of preference is studied. It is associated with the concept of pseudo-criterion derived from the classical concept of criterion by adjunction of two thresholds. Some results are given, generalizing the properties of such well-known structures as complete preorders and semiorders. Sections 5 and 6 emphasize the possibilities given by the preceding concepts to take the imprecisions, irresolutions and incomparabilities appearing in every concrete problem where several criteria must be considered into account.