The Dynamics of a Simple Relative Adjustment Cost Framework

This paper considers a capital accumulation model with the specific feature that adjustment costs depend on investment relative to the size of the capital stock. This framework has, beyond its plausible yet neglected setting, a number of interesting consequences. In particular, the possibility of multiple equilibria, of an unstable steady state and thus of a (`history dependent') threshold associated with concavity is surprising given a voluminous literature on multiple, history-dependent equilibria emphasizing non-concavities (or convexities).     

Chaotic consumption patterns in a simple2-D addiction model

Summary.  Consumption fluctuations in a simple 2-D addiction model are investigated. The behavioural equations of the model are suggested by a related ‘rational addiction’ model of Becker and Murphy [2]. Our model generates erratic, seemingly unpredictable consumption patterns of the addicted persons. The occurence of chaos is proven by locating a so called horseshoe map in the phase space. Received: April 4, 1994; revised version March 25, 1996     

Optimal pricing of a conspicuous product during a recession that freezes capital markets

This paper considers the problem of how to price a conspicuous product when the economy is in a recession that disrupts capital markets. A conspicuous product in this context is a luxury good for which demand is increasing in brand image. Brand image here means the ability of a consumer to impress observers by conspicuously displaying consumption of the good. Brand image is built up when the good is priced high enough to make it exclusive, and eroded if the good is discounted.Recession is modeled as having two effects: it reduces demand and it freezes capital markets so borrowing is not possible. In pricing the conspicuous product the firm faces the following trade-off. Reducing price helps maintain sales volume and cash flow in the face of reduced demand, but it also damages brand image and thus long-term demand.The paper analyzes the firm's pricing policy facing scenarios of mild, intermediate and severe recessions, while taking the threat of bankruptcy into account. For an intermediate recession the optimal solution is history-dependent. The results have implications for policy interventions in capital markets and for timing of mergers and acquisitions.     

Buchbesprechungen

Ohne Zusammenfassung     

Externalities in a life cycle model with endogenous survival

We study socially vs individually optimal life cycle allocations of consumption and health, when individual health care curbs own mortality but also has a spillover effect on other persons’ survival. Such spillovers arise, for instance, when health care activity at aggregate level triggers improvements in treatment through learning-by-doing (positive externality) or a deterioration in the quality of care through congestion (negative externality). We combine an age-structured optimal control model at population level with a conventional life cycle model to derive the social and private value of life. We then examine how individual incentives deviate from social incentives and how they can be aligned by way of a transfer scheme. The age-patterns of socially and individually optimal health expenditures and the transfer rate are derived. Numerical analysis illustrates the working of our model.     

„Wahrscheinlichkeitslernen“ in der statistischen Lerntheorie

Zusammenfassung In diesem Beitrag zur statistischen Lerntheorie (Stimulus Sampling Theorie) wird einN-elementiges „Pattern“-Modell mitr verfügbaren Antworten und nichtkontingenter Verst?rkungsvorschrift diskutiert. Um von der lerntheoretischen Literatur nicht zu sehr abh?ngig zu sein, wird zun?chst ein kanpper überblick über die Grundbegriffe der Stimulus Sampling Theorie gegeben. Der Vorgang des „Wahrscheinlichkeitslernens“ wird mittels des Reiz-Antwort-Schemas der statistischen Lerntheorie erkl?rt. Durch die Einführung der sogenannten bedingenden Zust?nde gelangt die Theorie derMarkovketten zur Anwendung. Schlie?lich wird das Problem der übereinstimmung von empirischen Daten aus Lernexperimenten mit den aus der Theorie abgeleiteten anhand von Sequentialstatistiken studiert.

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Summary In this contribution to the statistical learning theory (stimulus sampling theory) aN-element pattern model withr availables responses and noncontingent reinforcement schedule is discussed. First a short survey of the principles of the stimulus sampling theory is given. The process of „probability learning“ is explained by the stimulus-response model of the statistical theory of learning. By the introduction of the so-called conditioning states the theory ofMarkov chains may be applicated. Finaly, the goodness-of-fit between empirical data of learning experiments and predicted statistics is studied on the basis of sequential predictions.