Choice functions: rationality re-examined

On analyzing the problem that arises whenever the set of maximal elements i s large, and a selection is then required (see Peris & Subiza 1998), we rea lize that logical ways of selecting among maximals violate the classical no tion and axioms of rationality. We arrive at the same conclusion if we anal yze solutions to the problem of choosing from a tournament (where maximal e lements do not necessarily exist). So, in our opinion the notion of rationa lity must be discussed, not only in the traditional sense of external condi tions (Sen 1993), but in terms of the internal information provided by the binary relation.