Equilibrium selection through incomplete information in coordination games: An experimental study

We perform an experiment on a pure coordination game with uncertaintyabout the payoffs. Our game is closely related to models that have beenused in many macroeconomic and financial applications to solve problemsof equilibrium indeterminacy. In our experiment each subject receives anoisy signal about the true payoffs. This game has a unique strategyprofile that survives the iterative deletion of strictly dominatedstrategies (thus a unique Nash equilibrium). The equilibrium outcomecoincides, on average, with the risk-dominant equilibrium outcome ofthe underlying coordination game. The behavior of the subjects convergesto the theoretical prediction after enough experience has been gained. The data (and the comments) suggest that subjects do not apply through"a priori" reasoning the iterated deletion of dominated strategies.Instead, they adapt to the responses of other players. Thus, the lengthof the learning phase clearly varies for the different signals. We alsotest behavior in a game without uncertainty as a benchmark case. The gamewith uncertainty is inspired by the "global" games of Carlsson and VanDamme (1993).

Do expectations matter? The Great Moderation revisited

We examine the role of expectations in the Great Moderation episode. We derive theoretical restrictions in a New-Keynesian model and test them using measures of expectations obtained from survey data, the Greenbook and bond markets. Expectations explain the dynamics of inflation and of interest rates but their importance is roughly unchanged over time. Systems with and without expectations display similar reduced form characteristics. Including or excluding expectations hardly changes the economic explanation of the Great Moderation. Results are robust to changes in the structure of the empirical model.

Stable sunspot equilibria in a cash-in-advance economy

We analyze a monetary model with flexible labor supply, cash-inadvance constraints and seigniorage-financed government deficits. If the intertemporal elasticity of substitution of labor is greater than one, there are two steady states, one determinate and the other indeterminate. If the elasticity is less than one, there is a unique steady state, which can be indeterminate. Only in the latter case do there exist sunspot equilibria that are stable under adaptive learning. A sufficient reduction in government purchases can in many cases eliminate the sunspot equilibria while raising consumption/labor taxes even enough to balance the budget may fail to achieve determinacy.

A finite-population revenue management model and a risk-ratio procedure for the joint estimation of population size and parameters

Many dynamic revenue management models divide the sale period into a finite number of periods T and assume, invoking a fine-enough grid of time, that each period sees at most one booking request. These Poisson-type assumptions restrict the variability of the demand in the model, but researchers and practitioners were willing to overlook this for the benefit of tractability of the models. In this paper, we criticize this model from another angle. Estimating the discrete finite-period model poses problems of indeterminacy and non-robustness: Arbitrarily fixing T leads to arbitrary control values and on the other hand estimating T from data adds an additional layer of indeterminacy. To counter this, we first propose an alternate finite-population model that avoids this problem of fixing T and allows a wider range of demand distributions, while retaining the useful marginal-value properties of the finite-period model. The finite-population model still requires jointly estimating market size and the parameters of the customer purchase model without observing no-purchases. Estimation of market-size when no-purchases are unobservable has rarely been attempted in the marketing or revenue management literature. Indeed, we point out that it is akin to the classical statistical problem of estimating the parameters of a binomial distribution with unknown population size and success probability, and hence likely to be challenging. However, when the purchase probabilities are given by a functional form such as a multinomial-logit model, we propose an estimation heuristic that exploits the specification of the functional form, the variety of the offer sets in a typical RM setting, and qualitative knowledge of arrival rates. Finally we perform simulations to show that the estimator is very promising in obtaining unbiased estimates of population size and the model parameters.

The Spatial Effects of Trade Openness: A Survey

This paper surveys the literature on the implications of trade liberalisation for intra-national economic geographies. Three results stand out. First, neither urban systems models nor new economic geography models imply a robust prediction for the impact of trade openness on spatial concentration. Whether trade promotes concentration or dispersion depends on subtle modelling choices among which it is impossible to adjudicate a priori. Second, empirical evidence mirrors the theoretical indeterminacy: a majority of cross-country studies find no significant effect of openness on urban concentration or regional inequality. Third, the available models predict that, other things equal, regions with inherently less costly access to foreign markets, such as border or port regions, stand to reap the largest gains from trade liberalisation. This prediction is confirmed by the available evidence. Whether trade liberalisation raises or lowers regional inequality therefore depends on each country's specific geography.

Comparison of an EMG-based and a stress-based method to predict shoulder muscle forces.

The estimation of muscle forces in musculoskeletal shoulder models is still controversial. Two different methods are widely used to solve the indeterminacy of the system: electromyography (EMG)-based methods and stress-based methods. The goal of this work was to evaluate the influence of these two methods on the prediction of muscle forces, glenohumeral load and joint stability after total shoulder arthroplasty. An EMG-based and a stress-based method were implemented into the same musculoskeletal shoulder model. The model replicated the glenohumeral joint after total shoulder arthroplasty. It contained the scapula, the humerus, the joint prosthesis, the rotator cuff muscles supraspinatus, subscapularis and infraspinatus and the middle, anterior and posterior deltoid muscles. A movement of abduction was simulated in the plane of the scapula. The EMG-based method replicated muscular activity of experimentally measured EMG. The stress-based method minimised a cost function based on muscle stresses. We compared muscle forces, joint reaction force, articular contact pressure and translation of the humeral head. The stress-based method predicted a lower force of the rotator cuff muscles. This was partly counter-balanced by a higher force of the middle part of the deltoid muscle. As a consequence, the stress-based method predicted a lower joint load (16% reduced) and a higher superior-inferior translation of the humeral head (increased by 1.2 mm). The EMG-based method has the advantage of replicating the observed cocontraction of stabilising muscles of the rotator cuff. This method is, however, limited to available EMG measurements. The stress-based method has thus an advantage of flexibility, but may overestimate glenohumeral subluxation.

A minimal set of coordinates for describing humanoid shoulder motion

The kinematics of the anatomical shoulder are analysed and modelled as a parallel mechanism similar to a Stewart platform. A new method is proposed to describe the shoulder kinematics with minimal coordinates and solve the indeterminacy. The minimal coordinates are defined from bony landmarks and the scapulothoracic kinematic constraints. Independent from one another, they uniquely characterise the shoulder motion. A humanoid mechanism is then proposed with identical kinematic properties. It is then shown how minimal coordinates can be obtained for this mechanism and how the coordinates simplify both the motion-planning task and trajectory-tracking control. Lastly, the coordinates are also shown to have an application in the field of biomechanics where they can be used to model the scapulohumeral rhythm.

Wittgenstein et le conventionnalisme : une critique du contextualisme sémantique de François Recanati

Dans Literal Meaning, François Recanati cherche à montrer que ce qui est dit lorsqu’une phrase est prononcée correspond à un contenu fondamentalement pragmatique. À cet effet, il propose deux arguments généraux qui consistent à faire valoir que ce qui est dit est indéterminé si l'on s'en tient aux règles de la sémantique. Le premier de ces deux arguments tente d’établir que dans bien des cas, le contenu sémantique supposément associé à une phrase ne correspond pas à ce qui est dit. Le second est plutôt une élaboration de la thèse wittgensteinienne suivant laquelle la signification des types linguistiques est indéterminée. Pour ma part, je soutiens que si nous adoptons effectivement une conception wittgensteinienne de la signification, certains des exemples supposés illustrer le premier de ces deux arguments peuvent et doivent être critiqués.

La justice globale et son rapport aux pratiques internationales : deux approches pour l’éradication de la pauvreté

Cette recherche a bénéficié du soutien de plusieurs organismes. D’abord, je remercie le Conseil de recherche en sciences humaines du Canada (CRSH) de m’avoir accordé la bourse J.A. Bombardier – bourse de recherche pour la maitrise. Je remercie également le département de philosophie pour les quelques bourses de recherche et de voyage qui m’ont été offertes au cours de mes études de deuxième cycle au département. Je tiens finalement à exprimer ma gratitude envers le Groupe de recherche interuniversitaire en philosophie politique (GRIPP) pour son soutient financier ainsi que pour l’expérience enrichissante qu’il m’a promulgué. Une partie de ce mémoire a été présentée en avril 2012 à la Graduate Conference on Global Justice, tenue à la Gallatin School, New York University.

Equality of Opportunity in Public Employment : Judicial Perspectives on Backwardness

This thesis is a study of -Equality of Opportunity in Public Employment : Judicial Perspectives on Backwardness. This study is an attempt to evaluate the concept of backwardness and equality of opportunity in employment and to assess the judicial perspectives in relation to them. The study reveals that the recent review petition of the Constitution Bench did not assess the decision of Chakradhar and its import. The study reveals that the Indian judiciary could successfully locate and apply the above principles. It was-Justice Subba Rao's nascent attempt in Devadasan which marked the starting point of such a jurisprudential enquiry. Later Thomas developed the thoughts by a reading new meaning and content to equality provisions of the Constitution which included the elimination of inequalities as the positive content of Articles 14 and 16(1) and elevated reservation provision to the same status of equality principles under the Constitution. Soshit, Vasanth Kumar and Mandal supplemented further to the jurisprudential contents. In this process, the courts were guided by the theories of John Rawls, David Miller, Ronald Dworkin, Max Weber and Roscoe Pound. Thus there was a slow and steady process of transformation of the reservation provision. From an anti-meritarian, unenforceable and enabling provision, it reached a stage of equally relevant and explanatory part of fundamental right to equality. Mandal viewed it as a part of sharing of State power. Though this can be seen by rereading and re-joining thoughts of judges in this regard, the judicial approach lacks coherence and concerted efforts in evolving a jurisprudential basis for protective discrimination. The deliberations of the framers of the Constitution reveals that there was much confusion and indeterminacy with regard to the concept of Backwardness. The study shows that the judiciary has been keeping intact the framers’ expectation of having a reasonable quantum of reservation, preventing the undeserved sections from enjoying the benefit, avoiding its abuse and evolving a new criteria and rejecting the old ones.

Onset And Characterisation Of Chaos In A Two Dimensional Nonlinear Deterministic Model

Nature is full of phenomena which we call "chaotic", the weather being a prime example. What we mean by this is that we cannot predict it to any significant accuracy, either because the system is inherently complex, or because some of the governing factors are not deterministic. However, during recent years it has become clear that random behaviour can occur even in very simple systems with very few number of degrees of freedom, without any need for complexity or indeterminacy. The discovery that chaos can be generated even with the help of systems having completely deterministic rules - often models of natural phenomena - has stimulated a lo; of research interest recently. Not that this chaos has no underlying order, but it is of a subtle kind, that has taken a great deal of ingenuity to unravel. In the present thesis, the author introduce a new nonlinear model, a ‘modulated’ logistic map, and analyse it from the view point of ‘deterministic chaos‘.

Contra los métodos en el Derecho Internacional: una crítica a partir de su contribución para la realización de la función social de la dogmática jurídica

Este artículo tiene como objetivo investigar la utilidad de los métodos para el cumplimiento de la función social de la dogmática jurídica. En este contexto, los métodos son presentados como instrumentos para formular respuestas más precisas en el ámbito de la práctica jurídica. Se intentará demostrar la imposibilidad ontológica de logro en esta tarea. Los métodos no pueden conferir más certidumbre a los argumentos dogmáticos. Para poder demostrarlo, a través de investigación bibliográfica, se expondrá el debate sobre el método en la actualidad de la academia jurídica internacional, para después dedicarse a un ejemplo que sirve de punto de partida para el análisis del problema: la indeterminación del contenido de la costumbre internacional. Con base en los métodos más conocidos, se investigan las respuestas que pueden ofrecer al problema práctico de la costumbre. El resultado es negativo, lo que comprueba la hipótesis inicial: hay que abandonar el sueño de un método teórico de modelo deductivo para dar certidumbre a la "ciencia" del Derecho.

La indeterminación del campo de la Justicia Transicional en Colombia

La justicia transicional debe enfrentar la negación de las atrocidades. A pesar de la sofisticación del marco de derechos humanos presente en el sistema legal colombiano, el campo de la justicia transicional en Colombia adolece de un significativo grado de indeterminación normativa, como si dicho campo aconteciera en un vacío constitucional”. Como consecuencia, ha sido objeto de uso estratégico por parte de distintos actores políticos dotados de intencionalidad en la fijación del sentido del arreglo institucional de la llamada justicia transicional. El uso estratégico gravita entre el acatamiento pleno del marco de derechos humanos o su elusión en distintos grados. La elusión niega las atrocidades. Para que el discurso de la justicia transicional en Colombia contribuya a hacer justicia por las atrocidades, debe dar viabilidad práctica a los derechos de las víctimas, no reducir esos estándares. Para ello, son necesarios dos requisitos: desde el punto de vista sustantivo, debe acatar las obligaciones en materia de verdad, justicia y reparación, que son parámetro de constitucionalidad, y respetar el núcleo esencial de tales derechos, sin perjuicio de la libertad de configuración legislativa y de la ponderación judicial. Desde el punto de vista procedimental, debe adoptar como metodología un enfoque contextualizado de análisis comparado que evite el trasplante acrítico de experiencias internacionales inaplicables.

Salud y crecimiento económico: un modelo de generaciones traslapadas, expectativa de vida endógena y capital humano

Este trabajo desarrolla un modelo de generaciones traslapadas con expectativa de vida endógena y capital humano. Recoge parte de la evidencia empírica acerca de la transición demográfica explicada por Notestein en 1945, donde variaciones en la longevidad de los individuos afectan positivamente el crecimiento económico de un país. El modelo establece que la falta de incentivos para invertir en salud estanca a una economía en una trampa de pobreza y muestra que incrementos en la productividad en el sector de producción de capital humano, al igual que cambios tecnológicos sesgados al uso intensivo del mismo, incrementan el producto de estado estacionario y pueden sacar a una economía de una trampa de pobreza.

Deber judicial de resolución y casos difíciles (Tema Central)

Resolver por parte de los operadores jurídicos y en los casos en los que el derecho aplicable es indeterminado, con mecanismos y técnicas que son asimismo imprecisas, genera ciertas consecuencias: en estos supuestos los jueces no cuentan con criterios nítidos que guíen su toma de decisiones. dado que la extensión de lo indeterminado es indeterminada, la indeterminación es ineliminable no solo del contenido de las reglas jurídicas sino también de los recursos y mecanismos interpretativos del derecho. Así sucede en los “casos difíciles”, en los que el “deber de resolución” que impone a los jueces el Estado de derecho deviene impreciso y de realización incierta.