Contributions in Merlin

Bill and Herb have provided an illuminating and interesting presentation of Irving Fisher's Ph.D. dissertation Mathematical Investigations in the Theory of Value and Prices. They correctly emphasize that Fisher's fundamental contribution to the early theory of general equilibrium was the construction of a machine to compute the equilibrium quantities in a Walrasian model of competitive markets. As Fisher notes, Walras deserves priority for deriving a system of equations that characterize equilibrium in competitive markets. Even in this area, however, Fisher makes a subtle and interesting contribution in his system of equilibrium equations, discussed later. The first modern treatment of computing equilibrium prices in Walrasian economies is due to Herb, as everyone in this audience knows. His seminal paper, “On the Computation of Equilibrium Prices,” appears, most appropriately, in Ten Essays in Honor of Irving Fisher. The modern treatment of the existence question in the general equilibrium model, due to Arrow and Debreu, converts the equilibrium conditions into a fixed point of a continuous map, say from the price simplex into itself. It follows from Brouwer's fixed point theorem that this map will have a fixed point. The Scarf algorithm computes approximate fixed points of any continuous map of the simplex into itself. Hence the Scarf algorithm can be used to compute equilibrium quantities. Subsequent to Scarf's research, a more direct method of solving nonlinear systems of equilibrium equations was suggested by Eaves. The so-called homotopy method deforms a set of equations whose solution we know into the equilibrium equations, tracing out a path of solutions terminating in a solution for the equilibrium equations. Unfortunately, there is no price-adjustment interpretation of the disequilibrium prices along the homotopy path. In this way they are similar to the prices generated by the Fisher machine out of equilibrium. Below we give a system of equations characterizing equilibrium in an exchange economy with two agents and three goods. Agents are assumed to be endowed with money income and additive separable utility functions, which are monotone, strictly concave, and smooth. The unknowns in our equations are the state variables of Fisher's machine, in other words, prices, individual consumptions, expenditures, marginal utilities of income, and marginal utilities of the consumptions implied by expenditures and prices. Equilibrium values are computed using the homotopy method.

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Printmedienmärkte weisen eine Reihe besonderer Eigenschaften auf, die sie von gewöhnlichen Produktmärkten unterscheiden. Die beiden wichtigsten dieser abgrenzenden Charakteristika sind (i) die direkte Abhängigkeit von Printmedienreichweite und Nachfrage nach Anzeigenseiten und (ii) die starke Fixkostendegression. Diese Arbeit zeigt aus wirtschaftstheoretischer Sicht, dass die Verbundenheit von Anzeigen- und Lesermarkt zu einer Reduktion der Anreize von Printmedienpreiserhöhungen im Fusionsfalle führt. Sie macht ebenso deutlich, dass die Fixkostendegression zu Effizienzgewinnen im Fusionsfall führen kann.

Ce cas décrit la structure organisationnelle en place dans une régie régionale de la santé et des services sociaux, ainsi que le processus de prise de décision pour un dossier particulier : la mise en œuvre d'un programme d'interruption volontaire de grossesses dans la région. L'objectif est d'illustrer comment la structure organisationnelle peut influencer (positivement ou négativement) la façon de traiter les dossiers et les résultats qui en découlent.

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The stakeholder view of the corporation holds that the capacity of a business enterprise is to generate long-term value, which depends on critical stakeholders. This paper proposes a learning framework to explain why and how firms adopt a broader respectively changed stakeholder orientation or why they do not. Therefore, insights gained by a former research project will be updated and extended (see Post et al. 2002b). Using concepts from organizational evolution, a dynamic three-stage frame-work will be developed in order to analysed the paths of a firm's stakeholder orientation in practice and over longer periods of time. Preliminary results from case studies of three large and complex firms are used to illustrate the development of propositions and show first empirical evidence that the framework works in identifying generic learning processes and longitudinally capturing the development of stakeholder management in practice

In this paper we explore the algorithmic space in which stripification, simplification and geometric compression of triangulated 2-manifolds overlap. Edge-collapse/uncollapse based geometric simplification algorithms develop a hierarchy of collapses such that during uncollapse the reverse order has to be maintained. We show that restricting the simplification and refinement operations only to, what we call, the collapsible edges creates hierarchyless simplification in which the operations on one edge can be performed independent of those on another. Although only a restricted set of edges is used for simplification operations, we prove topological results to show that, with minor retriangulation, any triangulated 2-manifold can be reduced to either a single vertex or a single edge using the hierarchyless simplification, resulting in extreme simplification. The set of collapsible edges helps us analyze and relate the similarities between simplification, stripification and geometric compression algorithms. We show that the maximal set of collapsible edges implicitly describes a triangle strip representation of the original model. Further, these strips can be effortlessly maintained on multiresolution models obtained through any sequence of hierarchyless simplifications on these collapsible edges. Due to natural relationship between stripification and geometric compression, these multi-resolution models can also be efficiently compressed using traditional compression algorithms. We present algorithms to find the maximal set of collapsible edges and to reorganize these edges to get the minimum number of connected components of these edges. An order-independent simplification and refinement of these edges is achieved by our novel data structure and we show the results of our implementation of view-dependent, dynamic, hierarchyless simplification. We maintain a single triangle strip across all multi-resolution models created by the view-dependent simplification process. We present a new algorithm to compress the models using the triangle strips implicitly defined by the collapsible edges.