  The aim of this paper is to propose a generalization of previous approaches
in qualitative decision making. Our work is based on the binary possibilistic
utility (PU), which is a possibilistic counterpart of Expected Utility (EU).We
first provide a new axiomatization of PU and study its relation with the
lexicographic aggregation of pessimistic and optimistic utilities. Then we
explain the reasons of the coarseness of qualitative decision criteria.
Finally, thanks to a redefinition of possibilistic lotteries and mixtures, we
present the refined binary possibilistic utility, which is more discriminating
than previously proposed criteria.
