M. Socorro Puy

The scoring rules in an endogenous election

Plurality rule is mostly criticized from being capable of choosing an alternative considered as worst by a strict majority. This paper considers elections in which the agenda consists of potential candidates strategically choosing whether or not to enter the election. In this context, we examine the ability of scoring rules to fulfil the Condorcet criterion. We show for the case of three potential candidates that Plurality rule is the only scoring rule that satisfies a version of the Condorcet criterion in two cases: 1) when preferences are single-peaked and, 2) when preferences are single-dipped.

Existence and Nash implementation of efficient sharing rules for a commonly owned technology

Abstract Suppose that a group of individuals owns collectively a technology which produces a consumption good by means of a (possibly heterogeneous) input. A sharing rule associates input contributions with a vector of consumptions that are technologically feasible. We show that the set of allocations obtained by any continuous sharing rule contains Pareto efficient allocations. We also present a mechanism that implements in Nash equilibrium the Pareto efficient allocations contained in an arbitrary sharing rule.

Individual rationality and voting in cooperative production

Abstract Suppose that a group of individuals owns collectively a technology which produces a consumption good from an input. A sharing rule associates input contributions with a vector of consumption. We consider sharing rules that are a convex combination of the Proportional, the Equal Share and the Equal Benefit Rules. We characterize the subset of sharing rules that satisfy Pareto efficiency and individual rationality. We also study the outcome of majority voting on this subselection of sharing rules.

External Equilibrium in Mobility and Redistribution Economies

We develop a simple model in which individuals, who are differentiated by skill levels, freely choose location among different regions. In each region there is a local labor market that determines the wage and a local redistributive taxation that is exogenously determined. Equilibrium requires that no agent wishes to migrate. We define some sufficient conditions for equilibrium, and we show that the greater the difference in mean skills across regions, the greater the difference in redistributive taxations across regions should be to avoid migration flows. A condition for uniqueness and stability of equilibrium is also provided. Copyright 2003 Blackwell Publishing Inc..

Asymmetric Single-peaked Preferences

Abstract The asymmetry of single-peaked preferences has scarcely been incorporated as an assumption in economic models. We analyze how to deal with asymmetric single-peaked preferences in a tractable way. We define natural types of asymmetries, provide the tools to compare degrees of asymmetry, and propose concrete utility functions that represent different directions and degrees of asymmetry. As an application, we provide a representative voter theorem which establishes the heterogeneity in degrees of asymmetry across agents that is compatible with the median being the representative voter.

Lobby Groups and the Financial Support of Election Campaigns

We study a model of competition between two political parties with policy compromise. There is aspecial interest group with well-defined preferences on political issues. Voters are of two kinds:impressionable and knowledgeable. The impressionable voters are influenced by the electioncampaigns. The objective of the parties is to obtain the maximum votes. Parties compete forfinancial support from a given interest group. Each party proposes a plataform in exchange for anamount of campaign funds, and the interest group decides whether to accept or reject each ofcampaign funds, and the interest group decides whether to accept or reject each of theseproposals. We show that parties competition resembles, to a certain extent, Bertrandcompetition. Furthermore, in equilibrium only one party gets funds from interest group. This resultdiffers from the one obtained in a similar model by Grossman and Helpman (1996a) (1996b), inwhich, in equlibrium, both parties are financed by the interest group. This differnce asisesbecause Grossman and Helpman assume that it is the interest group who makes the proposalsto the political parties.

Downsian Competition with Assembly Democracy

This chapter studies a scenario of political competition between two parties, a traditional downsian party and a party implementing assembly democracy. The latter party celebrates a pre-electoral assembly and a post-electoral assembly open to all who wish to take part in which citizens are invited to launch proposals and vote over them. The multiple proposals at the assembly generates a lottery over some policies which is evaluated by voters against the single policy proposed by the traditional party. We show that extremist assembly parties induce the traditional party to locate at the median policy position, whereas centrist assembly parties move the traditional party away from the median just in the opposite direction of the assembly’s median. Besides, we find that centrist assemblies, with respect to extremist assemblies, have more chances of winning the elections.

Stable coalition governments: the case of three political parties

We explore to what extent we can propose fixed negotiation rules and simple mechanisms (or protocols) that guarantee that political parties can form stable coalition governments. We analyze the case in which three parties can hold office in the form of two-party coalitions. We define a family of weighted rules that select political agreements as a function of the bliss points of the parties and electoral results (Gamson’s law and equal share among others are included). We show that every weighted rule yields a stable coalition. We use implementation theory to design a protocol (in the form of a mechanism) that guarantees that a stable coalition will govern. We find that no dominant solvable mechanism can be used for this purpose, but there is a simultaneous unanimity mechanism that implements it in Nash and strong Nash equilibrium. Finally, we analyze the case of a larger number of political parties.