17 November 2005, An interdisciplinary approach to coalition formation, Agnieszka Rusinowska (Nijmegen)
Dr Agnieszka Rusinowska
Radboud University Nijmegen
Nijmegen School of Management
An interdisciplinary approach to coalition formation
The presentation concerns an interdisciplinary approach to coalition formation. We apply the MacBeth software, relational algebra, the RelView tool, graph theory, bargaining theory, social choice theory, and consensus reaching to a certain model of coalition formation. The central notion of this model is the notion of a feasible stable government. Roughly speaking, a feasible government is a pair consisting of a (majority) coalition of parties and a policy supported by this coalition. Different governments may have different utilities (values) for different parties. Stability of a feasible government means that it is not dominated by another feasible one.
We use MacBeth (Measuring Attractiveness by a Categorical Based Evaluation Technique) to quantify the attractiveness and repulsiveness of feasible governments to parties, and to calculate the utilities of governments to parties. We formulate the notions of feasibility, dominance, and stability for governments in relation-algebraic terms. This enables us to use RelView, a tool for the visualization and manipulation of relations and for prototyping and relational programming, to compute the dominance relation and the set of all feasible stable governments. Using concepts of graph theory (initial strongly connected components, minimum feedback vertex sets), we present a procedure for choosing one government if the set of all stable governments is empty.