We study a market model where there are n different types of indivisible goods for sale. The goods can be substitutable or complementary. There are multiple units of each good. Each agent may consume several goods and has quasi-linear utilities in money. We introduce a general condition which...

This discussion paper resulted in a publication in 'Discrete Optimization', 2007, 4, 315-321.<P> In this paper an algorithm is proposed to find an integral solution of (nonlinear) complementarity problems. The algorithm starts with a nonnegative integral point and generates a unique sequence of...</p>

This discussion paper resulted in a publication in the 'SIAM Journal on Optimization', 2006, 16, 854-870. <P> It is well known that an upper semi-continuous compact- and convex-valued mapping fi from a nonempty compact and convex set X to the Euclidean space of which X is a subset has at least one...</p>

This discussion paper led to a publication in <A href="http://www.sciencedirect.com/science/article/pii/S0377221711004498">'European Journal of Operational Research'</A>, 214(3), 493-500.<P>We study the existence problem of a zero point of a function defined on a finite set of elements of the integer lattice of the n-dimensional Euclidean space. It is assumed that the set is...</p></a>

This discussion paper resulted in a publication in the 'SIAM Journal on Optimization', 2007, 18, 290-308. <P> In this paper we present two general results on the existence of a discrete zero point of a function from the n-dimensional integer lattice Zn to the n-dimensional Euclidean space Rn. Under...</p>

This discussion paper resulted in a publication in 'Mathematical Programming', ser. A, 2006, 108, 127-134. <P>

This discussion paper resulted in a publication in the 'Journal of Optimization Theory and Applications', 2010, 144, 391-407. <p> Tucker's well-known combinatorial lemma states that for any given symmetric triangulation of the n-dimensional unit cube and for any integer labeling that assigns to...</p>

We develop a new model of addictive behavior that takes as a starting point the classic rational addiction model of Becker and Murphy, but incorporates uncertainty. We model uncertainty through the Wiener stochastic process. This process captures both random events such as anxiety, tensions and...

We study a mean-variance capital asset pricing model (CAPM) in which investors have different probability beliefs about assets returns and different attitudes towards risk, all assets are risky, short-selling is allowed and satiation is possible. First, we prove that there exists a competitive...

It is well known that an upper semi-continuous compact- and convex-valued mapping fi from a nonempty compact and convex set X to the Euclidean space of which X is a subset has at least one stationary point, being a point in X at which the image fi(x) has a nonempty intersection with the normal...