Rivalry, Exclusion, and Coalitions

This paper analyzes a model where groups can attain exclusive ownership of a resource by means of a contest. We show that more concave production technologies and more egalitarianism within groups induce higher levels of social conflict. We then study endogenous coalition formation. Under cooperative exploitation of the resource, the grand coalition is the efficient partition but there exists a strong tendency toward bipartisan conflicts. Under noncooperative exploitation, conflict can ex ante Pareto dominate peaceful access and it becomes more difficult to support the grand coalition as a stable structure.     

Implementing partial tax harmonization in an asymmetric tax competition game with repeated interaction

This paper investigates the conditions under which partial harmonization for capital taxation is sustained in a repeated interactions model of tax competition when there are three countries with heterogenous capital endowments. We show that regardless of the structure of the coalition (i.e., full or partial tax coordination), whether partial tax harmonization is sustainable or not crucially depends on the extent to which the capital endowment of the medium‐sized country is similar to that of the large or small country. The most noteworthy finding is that the closer the capital endowment of the median country is to the average one, the less likely the tax harmonization including the median country is to prevail and the more likely the partial tax harmonization excluding the median country is to prevail. We also show that partial tax harmonization makes the member countries of the tax union better off and non‐member countries worse off, which stands in sharpe contrast with previous studies, such as Konrad and Schjelderup (1999) and Bucovetsky (2009).     

Global public goods and coalition formation under matching mechanisms

This paper links coalition theory with matching mechanisms in the presence of global public goods among heterogeneous players. This matching coalition may achieve Pareto‐improving outcomes while avoiding side payments. The paper characterizes conditions of coalition profitability and stability at both interior and corner equilibria. It is generally much harder to satisfy stability conditions than profitability conditions. A matching coalition is more profitable but less stable with a larger matching rate. Empirically there is no stable coalition but this can be overcome by introducing reputation mechanisms. There always exists a stable grand matching coalition if players value their reputation. The matching coalition faces a trade‐off between matching depth and breadth.     

Political cycle and reported labour incomes in Italy: Quasi-experimental evidence on tax evasion

Tax evasion is a complex phenomenon affected by many factors and shaped by policymakers' and citizens' behaviours. Distinct claims about the acceptability of tax evasion between centre-right and centre-left coalitions have clearly emerged in Italy in the last decades. According to the ruling coalition, these different attitudes could have influenced tax compliance, affecting reported incomes of the self-employed, who have much more room to engage in tax avoidance or evasion strategies than employees. Using a longitudinal administrative dataset recording the entire working life of the sampled individuals, we focus on the period 1996–2005 (the only period when a complete bipartisan political cycle took place in Italy) and, following a difference in differences design and carrying out fixed effects estimates, we test whether self-employed earnings, compared to employees earnings, significantly changed after the change in the ruling coalition. We find a clear reduction in self-employed reported earnings when the centre-right coalition ruled.

"Il prelievo fiscale corretto si aggira intorno a un terzo del reddito, se invece le tasse sono tra il 50 e 60% è troppo e così è giustificato mettere in atto l'elusione o l'evasione"."The correct tax burden is about one third of the income; it is too much if the tax burden is approximately 50 or 60%, thus it is justified to resort to tax avoidance or evasion."Silvio Berlusconi, speech during the electoral campaign, April 2008.

     

Null or nullifying players: The difference between the Shapley value and equal division solutions

A famous solution for cooperative transferable utility games is the Shapley value. Most axiomatic characterizations of this value use some axiom related to null players, i.e. players who contribute zero to any coalition. We show that replacing null players with nullifying players characterizes the equal division solution distributing the worth of the ‘grand coalition’ equally among all players. A player is nullifying if every coalition containing this player earns zero worth. Using invariance we provide similar characterizations of the equal surplus division solution assigning to every player its own worth, and distributing the remaining surplus equally among all players.     

A note on the core of an income redistribution game

We consider a redistribution of income by an n-person game in which each member is levied a proportional income tax under some fixed rule. It is shown that the redistribution that will be achieved by a specific negative income tax is in the core of the game, which means that the redistribution can not be upset by any coalition of members acting strategically to evade the full taxation.     

Core allocations and the dimension of the cone of efficiency price vectors

Let (R₁,…,R_k) be an arbitrary partition of the grand coalition in an atomless exchange economy with k “large enough.” We prove that an optimal allocation x belongs to the core if and only if x cannot be improved upon by any coalition that includes at least one of the R_i's. K is “large enough” if k ? r + 1, where r is the linear dimension of the cone P of the efficiency price vectors for x. Recall that it is always true that r ? n, when n is the number of commodities in the market, and that under differentiability and interiority r = 1; thus k can be chosen to be 2 (i.e., for any coalition R, an allocation x belongs to the core of the market if and only if x is not blocked by any coalition that either contains R or contains its complement).     

Cleaner Technologies and the Stability of International Environmental Agreements

This paper shows that if countries are farsighted when deciding whether to defect from a coalition, then the implementation of cleaner technologies, as embodied by a reduction in the emission per output ratio, may either improve or jeopardize the chances of reaching an international environmental agreement. A small change in the emission per output ratio can result in a discrete jump in the stable size of a coalition and global welfare evaluated under the stable coalition size. In the case of three countries, the grand coalition may be destabilized by the implementation of cleaner technologies, ultimately resulting in higher global emissions and lower global welfare. In the case of more than three countries, implementing cleaner technologies may result in a discrete jump, either upward or downward, of the largest stable coalition size and welfare. We examine both, the case of a flow and that of a stock pollutant. In the latter case, we show that the higher the stock of pollution at the instant when the cleaner technology is implemented, the more likely that a grand coalition of three countries is destabilized. Measures that enhance the natural rate of decay of stock pollutants are shown to have similar effects on the size of stable coalitions to reductions in the emission per output ratio.     

Tax Ratios in Macroeconomics: Do Taxes Really Matter?

In various empirical studies so-called tax ratios (tax revenues expressed as a ratio of some aggregate tax base) are employed as approximations for tax burdens. The most difficult problem in calculating tax ratios is the way in which personal income tax revenues are attributed to labour and capital. We argue that the methodology of Mendoza et al. (1994) is seriously flawed in this respect. Using information from national sources, we calculate more accurate tax ratios for eight OECD countries that differ substantially from those of Mendoza et al. (1997). Still, the results of the empirical analysis of Mendoza et al. (1997) do not change significantly if we use our tax ratios instead of those of Mendoza et al.. However, the results change once country specific effects are taken up in the model. Capital taxes are, e.g., shown to reduce economic growth. We find that the results of Daveri and Tabellini (2000) are neither sensitive to the use of the tax ratios nor to the specification of the model: high labour taxes have increased unemployment in Europe.     

Unique stability in simple coalition formation games

We investigate the uniqueness of stable coalition structures in a simple coalition formation model, for which specific coalition formation games, such as the marriage and roommate models, are special cases that are obtained by restricting the coalitions that may form. The main result is a characterization of collections of permissible coalitions which ensure that there is a unique stable coalition structure in the corresponding coalition formation model. In particular, we show that only single-lapping coalition formation models have a unique stable coalition structure for each preference profile, where single-lapping means that two coalitions cannot have more than one member in common, and coalitions do not form cycles. We also give another characterization using a graph representation, explore the implications of our results for matching models, and examine the existence of strategyproof coalition formation rules.     

Optimal shill bidding in the VCG mechanism

This paper studies shill bidding in the Vickrey?CClarke?CGroves (VCG) mechanism applied to combinatorial auctions. Shill bidding is a strategy whereby a single decision-maker enters the auction under the guise of multiple identities (Yokoo et?al. Games Econ Behav, 46?pp. 174?C188, 2004). I formulate the problem of optimal shill bidding for a bidder who knows the aggregate bid of her opponents. A key to the analysis is a subproblem??the cost minimization problem (CMP)??which searches for the cheapest way to win a given package using shills. An analysis of the CMP leads to several fundamental results about shill bidding: (i) I provide an exact characterization of the aggregate bids b such that some bidder would have an incentive to shill bid against b in terms of a new property Submodularity at the Top; (ii) the problem of optimally sponsoring shills is equivalent to the winner determination problem (for single minded bidders)??the problem of finding an efficient allocation in a combinatorial auction; (iii) shill bidding can occur in equilibrium; and (iv) the problem of shill bidding has an inverse, namely the collusive problem that a coalition of bidders may have an incentive to merge (even after competition among coalition members has been suppressed). I show that only when valuations are additive can the incentives to shill and merge simultaneously disappear.     

Partial International Coordination in the Great Fish War

This study extends the great fish war model of Levhari and Mirman [Levhari, D. and Mirman, L. (1980) Bell Journal of Economics 11: 322–344] by incorporating a multiple country context into the model and investigates the existence of a partial coordination Nash equilibrium. First, findings of this paper suggest that a partial coordination scheme is sustainable only in limited cases. Any coalition that has more than two member countries cannot be sustained. Second, the existence and the number of coordinating countries depend critically on the magnitude of the biological and preference parameters. Finally, if the coalition is assumed to be a dominant player, there always exist one or two welfare-improving sustainable coalitions and the size of the sustainable coalitions depends on the parameters of the problem.     

Did tax flattening affect RRSP contributions?

In 1988 marginal personal income tax rates changed in Canada, for some individuals by reasonably substantial amounts. In this note a large sample of tax‐filer data is examined and the conclusion is drawn that, when attention is paid to the possible confounding of marginal tax rate and non‐linear income effects, there is no convincing evidence that the tax rate changes affected contributions to Registered Retirement Saving Plans (RRSPs). Est‐ce que l'aplatissement des taux d'imposition influence les contributions au REER? En 1988, les taux marginaux d'imposition du revenu personnel ont changé au Canada, et, pour certaines personnes, ces changements ont été substantiels. Cette note examine un grand échantillon de rapports d'impôts et en arrive à la conclusion que, quand on prend en compte le mélange possible des effets du taux marginal d'imposition et des effets de revenu non‐linéaires, il n'y a pas de résultats qui montrent de façon probante que les changements dans les taux d'imposition ont influencé les contributions au REER.     

A comparative analysis of funding schemes for public infrastructure spending in Quebec

The economic literature has been investigating the positive relation between public infrastructure spending and the productivity of the private sector since Munnell (1992). We have introduced this relationship into a recursive dynamic computable general equilibrium model of the Quebec economy to investigate various funding schemes to scale up infrastructure spending in the province. We draw our assumptions from Estache et al. (2010) combined with sectoral elasticity parameters. We conduct a comparative analysis where the funding comes from debt alone, and debt with sales tax, income tax and business tax. Our main finding is that the income tax seems to produce the most positive effects and the businesses tax the most negative effects, though differences are small.     

Proto-coalition bargaining and the core

In the proto-coalition model of government formation, formateur F appoints a proto-coalition and asks its members whether to start negotiating a coalition contract. If all accept, then the proto-coalition forms and starts negotiating; otherwise, a caretaker government assumes office. I extend this model by allowing F to revise the chosen proto-coalition after rejections, that he states pre-conditions for the subsequent negotiations, and that F??s opponents may publicly pre-commit to accept/reject certain proposals. The set of equilibrium outcomes is identified as the core if F??s opponents can pre-commit and as the convex hull of the core if they cannot pre-commit credibly. This extended model eliminates two flaws of the standard model: it explains why F cannot always install his favored coalition (whatever the status quo) and why ??important?? coalition members may have more bargaining power in the subsequent negotiations than others.     

Convex Games and Stable Sets

It is well known that the core of a convex coalitional game with a finite set of players is the unique von Neumann–Morgenstern stable set of the game. We extend the definition of a stable set to coalitional games with an infinite set of players and give an example of a convex simple game with a countable set of players which does not have a stable set. But if a convex game with a countable set of players is continuous at the grand coalition, we prove that its core is the unique von Neumann–Morgenstern stable set. We also show that a game with a countable (possibly finite) set of players which is inner continuous is convex iff the core of each of its subgames is a stable set.Journal of Economic LiteratureClassification Numbers: C70, C71.     

Public Goods and Tax Competition in a Two‐Sided Market

A rather neglected issue in the tax competition literature is the dependence of equilibrium outcomes on the presence of firms and shoppers (two‐sided markets). Making use of a model of vertical and horizontal differentiation, within which jurisdictions compete by providing public goods and levying taxes in order to attract firms and shoppers, this paper characterizes the noncooperative equilibrium. It also evaluates the welfare implications for the jurisdictions of a popular policy of tax coordination: The imposition of a minimum tax. It is shown that the interaction of the two markets affects the intensity of tax competition and the degree of optimal vertical differentiation chosen by the competing jurisdictions. Though the noncooperative equilibrium is, as it is typically the case, inefficient such inefficiency is mitigated by the strength of the interaction in the two markets. A minimum tax policy is shown to be effective when the strength of the interaction is weak and ineffective when it is strong.     

The Stability of Hedonic Coalition Structures

We consider the partitioning of a society into coalitions in purely hedonic settings, i.e., where each player's payoff is completely determined by the identity of other members of her coalition. We first discuss how hedonic and nonhedonic settings differ and some sufficient conditions for the existence of core stable coalition partitions in hedonic settings. We then focus on a weaker stability condition: individual stability, where no player can benefit from moving to another coalition while not hurting the members of that new coalition. We show that if coalitions can be ordered according to some characteristic over which players have single-peaked preferences, or where players have symmetric and additively separable preferences, then there exists an individually stable coalition partition. Examples show that without these conditions, individually stable coalition partitions may not exist. We also discuss some other stability concepts, and the incompatibility of stability with other normative properties. Journal of Economic Literature Classification Numbers: C71, A14, D20.     

On the Least Core and the Mas-Colell Bargaining Set

We show that the least core of a TU coalitional game with a finite set of players is contained in the Mas-Colell bargaining set. This result is extended to games with a measurable space of players in which the worth of the grand coalition is at least that of any other coalition in the game. As a consequence, we obtain an existence theorem for the Mas-Colell bargaining set in TU games with a measurable space of players. Journal of Economic Literature Classification Number: C71.     

ON THE NEUTRALITY OF COALITION FORMATION IN A PURE BARGAINING PROBLEM*

We consider the sequential bargaining game à la Stahl–Binmore–Rubinstein with random proposers, juxtaposing an ex ante coalition formation stage to their bargaining game. On the basis of the expected outcomes in the negotiation over how to split a dollar, players can form coalitions in a sequential manner, within each of which they can redistribute their payoffs. It turns out that the grand coalition does form, and that each player receives his discounted expected payoff, which is obtained by playing as a single player in the negotiation, although there could be many equilibria in the bargaining stage.