We study decision under uncertainty in an Anscombe–Aumann framework. Two binary relations characterize a decision-maker: one incomplete relation, reflecting her objective rationality, and a second complete relation, reflecting her subjective rationality. We require the latter to be an extension of the former. Our key axiom is a dominance condition. Our main theorem provides a representation of the two relations. The objectively rational relation has a Bewley-style multiple prior representation. Using this set of priors, we fully characterize the subjectively rational relation (...) in terms of the most optimistic and most pessimistic expected utilities. (shrink)

This paper discusses the characteristic properties of List PR systems and FPTP systems, as given in Hout 2005 and Hout et al. 2006. While many of the properties we consider are common to both systems, it turns out (see Hout 2005) that the British system distinguishes itself by satisfying the district cancellation property, while the Dutch system distinguishes itself by satisfying consistency and anonymity. For scoring rules, topsonlyness is equivalent to being party fragmentation-proof (see Hout 2005; Hout et al. 2006). (...) One might present this as an argument in favour of requiring topsonlyness. However, we will also give counter-arguments against insisting upon the property of being party fragmentation-proof. (shrink)

This paper studies an economy whose agents perceive their consumption possibilities subjectively, and whose preferences are defined on what they subjectively experience, rather than on those alternatives that are objectively present. The model of agents' perceptions is based on intuitionistic logic. Roughly, this means that agents reason constructively: a solution to a problem exists only if there is a construction by which the problem can be solved. The theorems that can be proved determine how an agent perceives a set of (...) alternatives. A dual model relates perceived alternatives to a shared language, which the agents use in trading. So perceptions relate objective alternatives to an agent's subjective view of them, and reporting dually relates an agent's subjective world to a shared language. It turns out that an appropriately modified notion of competitive equilibrium always exists. However, in contrast with standard results in economic theory, competitive equilibrium need not be efficient. (shrink)

This paper discusses the characteristic properties of List PR systems and FPTP systems, as given in Hout 2005 and Hout et al. 2006. While many of the properties we consider are common to both systems, it turns out (see Hout 2005) that the British system distinguishes itself by satisfying the district cancellation property, while the Dutch system distinguishes itself by satisfying consistency and anonymity. For scoring rules, topsonlyness is equivalent to being party fragmentation-proof (see Hout 2005; Hout et al. 2006). (...) One might present this as an argument in favour of requiring topsonlyness. However, we will also give counter-arguments against insisting upon the property of being party fragmentation-proof. (shrink)