Claim-strength problems and mixtures: An axiomatic study

Claim-strength problems are a distinctive class of allocation problems in which the currency of claims is different from that of the estate that is to be divided. We study mixtures (i.e. convex combinations) of three basic allocation rules for claim-strength problems: the proportional rule, the uniform allocation rule, and the plurality allocation rule. We observe that any such mixture satisfies a generalized transfer axiom in addition to a number of invariance properties. We establish a fundamental representation theorem: taken jointly, these axioms fully characterize the class of all mixtures of the three base rules. This result is tight. From it, we derive characterizations of more specific classes and the three basic rules themselves. We moreover show that within the class of mixtures, the only three rules that satisfy a familiar consistency axiom are the base rules.