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>

<I>Abstract</I><p> See document.<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 each vertex of the triangulation a label from the set {1,2,...n,-1,-2,....-n} with the property that antipodal vertices on the...

In a standard general equilibrium model it is assumed that there are no price restictions and that prices adjust infinitely fast to their equilibrium values. In this paper the set of admissible prices is allowed to be an arbitrary convex set. For such an arbitrary set it cannot be guaranteed...

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 integrally convex, which implies that the convex hull of the set can be subdivided in simplices such that...

In this paper we present two general results on the existence of a discrete zero point of a function from the <I>n</I>-dimensional integer lattice Z<SUP><I>n</SUP></I> to the <I>n</I>-dimensional Euclidean space R<SUP><I>n</SUP></I>. Under two different boundary conditions, we give a constructive proof using a combinatorial argument based on a...</i></sup></i></i></sup></i>

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...

Any function from a non-empty polytope into itself that is locally gross direction preserving is shown to have the fixed point property. Brouwer's fixed point theorem for continuous functions is a special case. We discuss the application of the result in the area of non-cooperative game theory.