The purpose of this paper is to provide a characterization result for the canonical basis of an arbitrary closure operator. This theorem strengthens the result of Burosch, Demetrovics and Katona, who propose in [1] a characterization of the generating system of a closure operator defined by the...

In this paper, we study almost periodic (a.p.) solutions of discrete dynamical systems. We first adapt some results on a.p. differential equations to a.p. difference equations, on the link between boundedness of solutions and existence of a.p. solutions.

Kinckerbocker (1973) introduced "oligopolistic reaction" to explain why firms follow rivals into foreign markets. We develop a model that incorporates the central features of Kinckerbocker's story -oligopoly, uncertainty, and risk aversion- to establish the conditions required to generate...

We prove an integral representation theorem for functionals fulfilling some continuity conditions. These functionals satisfy a weaker condition than additivity, namely additive comonotonicity and do not need to be monotonic.

We show, in the Choquet expected utility model, that prefernece for diversification, that is, convex prefrences, is equivalent to a concave utility index and a convex capacity. We then introduce a weaker notion of diversification, namely "sure diversification". We show that this implies that the...

A usual argument in finance refers to no arbitrage opportunities for the positivity of the bid-ask spread. Here we follow the decision theory approach and show that if positivity of the bid-ask spread is identified with strong risk aversion for an expended utility market-marker, this is no...

This paper follows recent research about the importance, the variety and the development of innovation in the service industries. We study the innovations which have appeared in the fast growing activity of mobile telecommunication services in France.

The purpose of this paper is to examine how the Solow residual relates to innovation at the firm level. We estimate two kinds of relationships. The first relationship explains innovation output from innovation inputs. The second relationship relates TFP growth to innovation output.

The core of an economy consists of those states of the economy which no group of agents (coalition) can "improve upon". A coalition can improve upon a state of the economy if, by using the means available to that group, each member can be made better off. This paper presents the notion of the...