Finding a Nash equilibrium in spatial games is an NP-complete problem

Summary. We consider the class of (finite) spatial games. We show that the problem of determining whether there exists a Nash equilibrium in which each player has a payoff of at least k is NP-complete as a function of the number of players.Received: 15 September 2002, Revised: 9 March 2003, JEL Classification Numbers: C72.Correspondence to: H. HallerWe thank a referee for helpful comments. The hospitality of the Institute of Economics, University of Copenhagen, and the Institute for Advanced Studies, Vienna, is gratefully acknowledged by the third author.     

Does Increased Extraction of Natural Gas Reduce Carbon Emissions?

Without an international climate agreement, extraction of more natural gas could reduce emissions of CO₂ as more clean natural gas may drive out dirty coal and oil. Using a computable equilibrium model for the Western European electricity and natural gas markets, we examine whether increased extraction of natural gas in Norway reduces global emissions of CO₂. We find that both in the short run and in the long run total emissions are reduced if the additional quantity of natural gas is used in gas power production in Norway. If instead the additional quantity is exported directly, total emissions increase both in the short run and in the long run. However, if modest CO₂-taxes are imposed, increased extraction of natural gas will reduce CO₂ emissions also when the additional natural gas is exported directed.earlier version of this paper was presented at the 25th Annual IAEE International Conference in Aberdeen June 2002.     

Sequencing and the Adding-up Property in Contingent Valuation of Endangered Species: Are Contingent Non-Use Values Economic Values?

This paper presents tests of the theoretical validity of the contingent valuation (CV) method. The validity of CV is especially a concern when involving environmental goods with a predominant non-use value. One test of theoretical validity is the adding-up property that implies that a specific good should be equally valued irrespectively of it is being valued directly or built-up sequentially. In this CV study four independent sub-samples stated willingness to pay for the same composite good, or package, using different sequences. One sub-sample valued the composite good directly, while two sub-samples faced built-up sequences valuing first subsets of this composite good. A fourth sub-sample valued the composite good from a dividing-out approach, facing first the valuation of a larger multi-package. Theoretically expected sequencing effects were observed; the subset goods obtained higher values earlier in a sequence, and the dividing-out approach decreased the stated value for the composite good. Most importantly, these CV data did pass the tests of the adding-up property.     

Distribution Dynamics of CO<Subscript>2</Subscript> Emissions

This paper uses nonparametric methods to examine the convergence in CO₂ emissions per capita on a sample of 100 countries for the period 1966–1996. Industrial countries show a convergence pattern. However, there is little evidence of convergence for the whole sample.     

Joseph A. Schumpeter’s contributions in the area of fiscal sociology: a first approximation

Fiscal sociology deals with the ramifications of the fiscal activities of the state into areas which are not their primary target. These effects may occur in sectors not directly affected such as related markets, but they may also occur outside the economic sphere proper, such as in politics, culture, religion, or society at large. Schumpeter contributed to the research project of fiscal sociology throughout his life. In this first approximation, his contribution is discussed in terms of his appreciation of three important scholars who all made landmark contributions to fiscal sociology: Franz Oppenheimer, Werner Sombart, and Gustav (von) Schmoller.JEL Classification: B15, H39     

Double Dividend with Involuntary Unemployment: Efficiency and Intergenerational Equity

This paper analyzes the double dividend and distributional issues within an overlapping generations model framework with involuntary unemployment. We characterize the necessary conditions needed to obtain a double dividend, when the revenue of the environmental tax is recycled by a variation of the labor tax rate. We show that an employment dividend may occur without any efficiency dividend and that the young generation is not always harmed by the fiscal reform, even without any intergenerational transfers. Therefore, three dividends (environmental, efficiency and intergenerational equity) can occur simultaneously.     

Trees and decisions

Summary. The traditional model of sequential decision making, for instance, in extensive form games, is a tree. Most texts define a tree as a connected directed graph without loops and a distinguished node, called the root. But an abstract graph is not a domain for decision theory. Decision theory perceives of acts as functions from states to consequences. Sequential decisions, accordingly, get conceptualized by mappings from sets of states to sets of consequences. Thus, the question arises whether a natural definition of a tree can be given, where nodes are sets of states. We show that, indeed, trees can be defined as specific collections of sets. Without loss of generality the elements of these sets can be interpreted as representing plays. Therefore, the elements can serve as states and consequences at the same time.Received: 23 January 2003, Revised: 2 November 2003, JEL Classification Numbers: C72, D70. Correspondence to: Klaus RitzbergerWe are grateful to Larry Blume, Ariel Rubinstein, Jörgen Weibull, an anonymous referee, and seminar participants at the universities of Vienna, Salamanca, and Heidelberg for helpful comments. Financial support from the Austrian Science Fund (FWF) under project P15281 is also gratefully acknowledged.     

Pricing-to-market tests in instrumental regressions: Case of the transportation equipment industry

Pricing-to-market (PTM) theory suggests that exporting monopolistic firms adjust their destination-specific mark-ups in the face of exchange rate shocks. A large proportion of the existing evidence for PTM comes from Wald tests applied to OLS- and IV-estimated parameters of single-equation models. Such tests can seriously over-reject in the presence of endogeneity and weak instruments so that some of the available results supporting PTM could be spurious. In this paper we revisit the PTM evidence for Japanese and German exporting firms in the transportation equipment industry. Using the model of Marston (1990), we apply exogeneity and LR-LIML-based tests for which the error probability is controlled irrespective of the quality of the available instruments. Our results show right-hand-side endogeneity in almost all of the examined PTM equations. In addition, we find that statistical decisions often differ depending on whether they are based on the traditional Wald test or on our proposed test.The authors would like to thank Philippe Barla, Jean-Thomas Bernard, Christos Constantatos, Larry Schembri, seminar participants at the Bank of Canada, and two anonymous referees for useful comments and suggestions. Thanks also to Richard Marston for providing data. Finally, a special thanks to Marjorie Santos for excellent research assistance. All remaining errors are our own and should not be attributed to the Bank of Canada.First version received: May 2002/Final version received: December 2002     

Technology management in the company of the future

This paper develops new conceptual ideas on the role of technology management in future companies. It draws consequences for their operatins, and it suggests new perspectives that arise from current trends in company development. It argues that technology management needs to address, in a differentiated manner, the problems which airse during the development process of companies and markets. Particular emphasis is placed on the demand of systems producers on technology management.