Foundations for contest success functions

In the literature the outcome of contests is either interpreted as win probabilities or as shares of the prize. With this in mind, we examine two approaches to contest success functions. In the first we analyze the implications of contestants' incomplete information concerning the "type" of the contest administrator. While in the case of two contestants this approach can rationalize prominent contest success functions, we show that it runs into difficulties when there are more agents. Our second approach interprets contest success functions as sharing rules and establishes a connection to bargaining and claims problems which is independent of the number of contestants. Both approaches provide foundations for popular contest success functions and guidelines for the definition of new ones. Keywords: Endogenous Contests, Contest Success Function. JEL Classification: C72 (Noncooperative Games), D72 (Economic Models of Political Processes: Rent-Seeking, Elections), D74 (Conflict; Conflict Resolution; Alliances).

On Cobb-Douglas Preferences in Bilateral Oligopoly

Bilateral oligopoly is a simple model of exchange in which a finite set of sellers seek to exchange the goods they are endowed with for money with a finite set of buyers, and no price-taking assumptions are imposed. If trade takes place via a strategic market game bilateral oligopoly can be thought of as two linked proportional-sharing contests: in one the sellers share the aggregate bid from the buyers in proportion to their supply and in the other the buyers share the aggregate supply in proportion to their bids. The analysis can be separated into two ‘partial games’. First, fix the aggregate bid at B; in the first partial game the sellers contest this fixed prize in proportion to their supply and the aggregate supply in the equilibrium of this game is X˜ (B). Next, fix the aggregate supply at X; in the second partial game the buyers contest this fixed prize in proportion to their bids and the aggregate bid in the equilibrium of this game is ˜B (X). The analysis of these two partial games takes into account competition within each side of the market. Equilibrium in bilateral oligopoly must take into account competition between sellers and buyers and requires, for example, ˜B (X˜ (B)) = B. When all traders have Cobb-Douglas preferences ˜ X(B) does not depend on B and ˜B (X) does not depend on X: whilst there is competition within each side of the market there is no strategic interdependence between the sides of the market. The Cobb-Douglas assumption provides a tractable framework in which to explore the features of fully strategic trade but it misses perhaps the most interesting feature of bilateral oligopoly, the implications of which are investigated.

An axiomatization of difference-form contest success functions

This paper presents an axiomatic characterization of difference-form group contests, that is, contests fought among groups and where their probability of victory depends on the difference of their effective efforts. This axiomatization rests on the property of Equalizing Consistency, stating that the difference between winning probabilities in the grand contest and in the smaller contest should be identical across all participants in the smaller contest. This property overcomes some of the drawbacks of the widely-used ratio-form contest success functions. Our characterization shows that the criticisms commonly-held against difference-form contests success functions, such as lack of scale invariance and zero elasticity of augmentation, are unfounded.By clarifying the properties of this family of contest success functions, this axiomatization can help researchers to find the functional form better suited to their application of interest.

Bilateral oligopoly and quantity competition

Bilateral oligopoly is a strategic market game with two commodities, allowing strategic behavior on both sides of the market. When the number of buyers is large, such a game approximates a game of quantity competition played by sellers. We present examples which show that this is not typically a Cournot game. Rather, we introduce an alternative game of quantity competition (the market share game) and, appealing to results in the literature on contests, show that this yields the same equilibria as the many-buyer limit of bilateral oligopoly, under standard assumptions on costs and preferences. We also show that the market share and Cournot games have the same equilibria if and only if the price elasticity of the latter is one. These results lead to necessary and sufficient conditions for the Cournot game to be a good approximation to bilateral oligopoly with many buyers and to an ordering of total output when they are not satisfied.

Scepticism Revisited

Liberalism claims that for a subject S to be justified in believing p, a proposition about the external world, on the basis of his senses it is not necessary to be antecedently justified in believing propositions as there is an external world. On the other hand, conservatism claims that to be justified in believing that p on the basis of one’s perception, one must have antecedent justification to believe that p. Intuitively, we are inclined to think that liberalism about the structure of perceptual justification fits better with our epistemic practices. We acknowledge that, although we cannot produce warrant for the background belief in the external world, our empirical beliefs can be perceptually justified. However, I am interested in arguing that conservatism is theoretically better supported than liberalism. The first reason to defend this is based on the fact that in embracing liberalism dogmatism is affected by pervasive problems. The second one comes from recognizing the strength of the argument based on the thesis that experience is theory-laden. But not all are advantages for conservatism. Conservatism is presupposed in contemporary formulations of scepticism through the requirement of prior justification for background assumptions, and this fact compels anti-sceptical conservatives to conceive a non-evidential form of warrant, entitlement, to contest the sceptical threat My main worry is that, although the path of entitlement has some prospects to succeed, this new notion of justification seems to be posed ad hoc for conservatives to solve the sceptical problem. These contents are organized along the three chapters. The result of chapter 1 is a pattern of sceptical argument formed by two premises: P1*, a conservative principle, and P2*. In chapter 2 and chapter 3 two anti-sceptical proposals against the argument sketched in chapter 1 are described. Chapter 2 is devoted to explain and assess a first anti-sceptical proposal that denies P1*: dogmatism. Moreover, in chapter 3, another anti-sceptical strategy is described (the route of entitlement) that contests scepticism denying the plausibility of P2*.

Welfare Maximizing Contest Success Functions when the Planner Cannot Commit

We analyze how a contest organizer chooses optimally the winner when the contestants' efforts are already exerted and commitment to the use of a given contest success function is not possible. We de…ne the notion of rationalizability in mixed-strategies to capture such a situation. Our approach allows to derive different contest success functions depending on the aims and attitudes of the decider. We derive contest success functions which are closely related to commonly used functions providing new support for them. By taking into account social welfare considerations our approach bridges the contest literature and the recent literature on political economy. Keywords: Endogenous Contests, Contest Success Function, Mixed-Strategies. JEL Classi…cation: C72 (Noncooperative Games), D72 (Economic Models of Political Processes: Rent-Seeking, Elections), D74 (Conflict; Conflict Resolution; Alliances)

XVI Olimpíada Nacional de Química 2002-2003

Article que es refereix a la XVI Olimpíada Nacional de Química (2002 – 2003), celebrada el 9-12 de maig de 2003, al Seminari Menor de Tarazona (Saragossa). L’ olimpíada consisteix en dues proves: la primera consisteix en la resolució de 4 problemes llargs, i la segona en 45 preguntes de resposta múltiple (tipus test) que contenen qüestions teòriques i problemes curt. En aquest article s’ esmenten els alumnes que han obtingut alguna mena de distinció, els classificats per a la Fase Nacional, els problemes proposats i les característiques de les preguntes del test

XVIII Olimpíada Nacional de Química 2004-2005

Article que es refereix a la XVIII Olimpíada Nacional de Química (2004 – 2005), celebrada el 15-18 d' abril de 2005, al Luarca(Astúries). L’ olimpíada consisteix en dues proves: la primera consisteix en la resolució de 4 problemes llargs, i la segona en 45 preguntes de resposta múltiple (tipus test) que contenen qüestions teòriques i problemes curts. En aquest article s’ esmenten els alumnes que han obtingut algun tipus de distinció, els classificats per a la Fase Nacional, els problemes proposats i les característiques de les preguntes del test

The combination of social and personal contexts affects dominance hierarchy development in shore crabs, Carcinus maenas

Many animals that live in groups maintain competitive relationships, yet avoid continual fighting, by forming dominance hierarchies. We compare predictions of stochastic, individual-based models with empirical experimental evidence using shore crabs to test competing hypotheses regarding hierarchy development. The models test (1) what information individuals use when deciding to fight or retreat, (2) how past experience affects current resource-holding potential, and (3) how individuals deal with changes to the social environment. First, we conclude that crabs assess only their own state and not their opponent's when deciding to fight or retreat. Second, willingness to enter, and performance in, aggressive contests are influenced by previous contest outcomes. Winning increases the likelihood of both fighting and winning future interactions, while losing has the opposite effect. Third, when groups with established dominance hierarchies dissolve and new groups form, individuals reassess their ranks, showing no memory of previous rank or group affiliation. With every change in group composition, individuals fight for their new ranks. This iterative process carries over as groups dissolve and form, which has important implications for the relationship between ability and hierarchy rank. We conclude that dominance hierarchies emerge through an interaction of individual and social factors, and discuss these findings in terms of an underlying mechanism. Overall, our results are consistent with crabs using a cumulative assessment strategy iterated across changes in group composition, in which aggression is constrained by an absolute threshold in energy spent and damage received while fighting.

Construcció d’habitatges protegits a Gazzera Mattuglie, Venècia

Concurs per a l’encàrrec de l’avantprojecte i projecte bàsic de construcció d’habitatges protegits a Gazzera Mattuglie, Venècia

TRENats

Procedimiento restringido y concurso de proyectos con intervención de jurado, de los servicios para la redacción de los proyectos de Urbanización y Construcción de las fases 1ª, 2ª Y 3ª del Parque Lineal de la Sagrera – Sant Andreu en Barcelona