Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
First, a general qualification rule based on individual preferences is proposed which allows any given coalition to distinguish among its members some individuals who are said to be qualified by it since sensitive in preferences with all individuals of this coalition. A particular qualification rule, the liberal one, is then introduced as a rule conferring the power to qualify or disqualify any individual on the individual himself. Now, since each preference property corresponds to a qualification property, the liberal qualification rule is precisely characterized by individual preferences. Second, a delegator, that is a mapping describing a subset of delegates within the society, is defined to justify the standard notion of decisiveness. The idea of delegation allows us to generalize Arrow-Sen framework. This is done by means of a collective rationality postulate such that a coalition must be competent, i.e. includes all delegates, to be decisive. Then, we prove that (1) there exists a delegate who is qualified by any coalition he belongs to, (2) such a delegate is a dictator iff the qualification rule is liberal, (3) the qualification rule is liberal iff the preferences are selfish. Copyright 2003 by Kluwer Academic Publishers