Hans Keiding

Existence of equilibrium actions and of equilibrium: A note on the ‘new’ existence theorems☆

Abstract A lemma by Ky Fan, which asserts the existence of a maximal element relative to some ordering (an equilibrium action) in a compact choice set, is extended to a larger class of orderings. This extension allows one to generalize slightly several existence theorems and seems to be useful for the applications. Kakutanis fixed-point theorem and the existence of an equilibrium in a generalized game are used to exemplify this. In the last case the method of proof may be of some independent interest involving, as it does, the reduction of an n -person game to a corresponding 1-person game.

A cost-effectiveness analysis of immunotherapy with SQ allergen extract for patients with seasonal allergic rhinoconjunctivitis in selected European countries

ABSTRACT Background: Seasonal allergic rhinoconjunctivitis can, for some people, reduce quality of life and the ability to cope with everyday tasks. Scope: In this paper we investigate the cost-effectiveness of immunization therapy with Alutard SQ (ASQ) and compare the cost-effectiveness in countries where the therapy has been in use in order to assess the impact of national therapeutic practices on the results of health economic assessments. Data are obtained from a clinical trial carried out in 2001–2002. To evaluate the cost-effectiveness of immunization we have added data on resource use in Austria, Denmark, Finland, Germany, the Netherlands, and Sweden. Findings: The computations result in cost-effectiveness ratios for allergen immunization between €10 000 and €20 000 per QALY even without provision for indirect costs, and achieving dominance in most countries where indirect costs have also been taken into account. The country comparisons show that the direct cost of administrating the up-dosing and maintenance differs considerably between countries, and that the cost of medical staff is substantial, constituting in most cases more than half of the direct costs of the immunization therapy. Conclusion: The study shows that immunotherapy with SQ allergen extract is cost-effective in a wide range of national environments, and that cost-effectiveness differences by country are largely a result of different practices in the up-dosing phase.

Necessary and sufficient conditions for stability of effectivity functions

An effectivity functionE assigns to every coalitionS of players a familyE (S) of subsetsB of an outcome setA such thatS can force the outcome to belong to any of the setsB inE (S). The effectivity functionE is stable if for every preference profile there is an outcomex with the property that there is no coalitionS and subsetB ofA such thatB εE (S) and each player inS prefers everyy εB tox.The paper gives a necessary and sufficient condition for an effectivity function to be stable.

An axiomatization of the core of a cooperative game

Abstract In this paper we present a set of axioms on outcomes of cooperative games without side payments which, together with a minimality condition, characterize the core.

The core of a cooperative game without side payments

For cooperative games without side payments, there are several types of conditions which guarantee nonemptiness of the core, for example balancedness and convexity. In the present paper, a general condition for nonempty core is introduced which includes the known ones as special cases. Moreover, it is shown that every game with nonempty core satisfies this condition.

The solidarity axiom in parametric surplus-sharing problems

A parametric surplus-sharing problem is given by a set X of feasible utility vectors and a disagreement utility vector d, both depending upon an exogenous parameter. We examine the existence of a surplus-sharing solution such that the outcomes selected in any two problems are Pareto comparable. We characterize existence and show how to apply this result to several micro-economic problems. These problems include distribution of private goods, production economies where the production process is jointly owned and collusion in an oligopoly.

A Relationship between optimality and efficiency in multicriteria 0–1 programming problems

Abstract An efficient or nondominated solution to a multicriteria minimization problem is a feasible solution for which a decrease in the value of any criterion can only be obtained if the value of at least one other criterion is increased. Interest in the conditions under which solutions to multicriteria programming problems can be shown to be efficient has grown enormously in recent years, not least of all due to the awareness that significant planning problems can only be meaningfully modelled if multiple measures of effectiveness are considered. However, the broad class of multicriteria 0–1 programming problems, which are of great practical importance, has received only limited attention in the literature. We establish the identity of the set of efficient solutions with respect to such multicriteria programming problems with any criteria and any constraint set and the set of optimal solutions to a parametrized unicriterion problem incorporating these criteria. Illustrative numerical examples are provided.

Representation of preferences on fuzzy measures by a fuzzy integral

Abstract In recent research on decisions under uncertainty, the basic universe of choice has been extended from probability distributions (additive set functions) to set functions that are not necessarily additive. This family has been investigated in other contexts under the name of fuzzy measures, and there exists a theory of (fuzzy) integration for fuzzy measures. In the present paper this concept of an integral is used in a utility representation of preferences on the set of non-additive set functions. A system of axioms for such a representation is presented, and its usefulness with respect to decision theory is evaluated.

Evaluating sustainability of household consumption—Using DEA to assess environmental performance

Abstract We assess environmental performance across product types and across household types in order to evaluate environmental pressure from human activities. To so do, we combine family budget statistics, input–output tables, energy and material flow matrices, various types of emissions and environmental effects indices for various effect types (e.g. a global warming potential index, an ozone depletion potential index, etc). Subsequently, using DEA (Data Envelopment Analysis), we use these weighted environmental effects indices to form one environ-mental performance score for each family type and product type. We find that the environmental performance of each family type changes considerably across environmental effect types. The analysis of the overall environmental performance scores shows that families living in urban flats, especially the young and elderly families, have the most environmentally friendly consum-ption pattern. Middle income families living in houses have the least environmentally friendly consumer basket, and these families constitute a high share of all families in Denmark.

Alternative health insurance schemes: a welfare comparison

In this paper, we present a simple model of health insurance with asymmetric information, where we compare two alternative ways of organizing the insurance market. Either as a competitive insurance market, where some risks remain uninsured, or as a compulsory scheme, where however, the level of reimbursement of loss is to be determined by majority decision. In a simple welfare comparison, the compulsory scheme may in certain environments yield a solution which is inferior to that obtained in the market. We further consider the situation where the compulsory scheme may be supplemented by voluntary competitive insurance; this situation turns out to be at least as good as either of the alternatives.