Focusing on the testable revealed preference restrictions on the equilibrium manifold, we show that the rationalizability problem is NP-complete. Subsequently, we present a mixed integer programming (MIP) approach to characterize the testable implications of general equilibrium models....

We consider a special case of the directed subgraph homeomorphism or topological minor problem, where the host graph has a specific regular structure. Given an acyclic directed pattern graph, we are looking for a host graph of minimal height which still allows for an embedding. This problem has...

In this paper we investigate a vehicle routing problem motivated by a real-world application in cooperation with the German Automobile Association (ADAC). The general task is to assign service requests to service units and to plan tours for the units such as to minimize the overall cost. The...

In this paper we give an overview of various methods used to study cooperation within a set of players. Besides the classical games with transferable utility and games without transferable utility, recently new models have been proposed: the coalition formation games. In these, each player has...

Electronic voting systems are no longer a theoretical matter and they have been successfully used in elections and referendums in some countries. With such systems some problems of paper ballots can be eliminated easily. However, these systems have their own security problems. In this article,...