Disconnecting graphs by removing vertices: a polyhedral approach

In this paper, we consider the problem of disconnecting a graph by removing as few vertices as possible, such that no component of the disconnected graph has more than a given number of vertices. We give applications of this problem, present a formulation for it, and describe some polyhedral results. Furthermore, we establish ties with other polytopes and show how these relations can be used to obtain facets of our polytope. Finally, we give some computational results.     

Models of democracy in spatial investments

Governance regarding spatial investments meets or even creates institutional tensions that process management finds difficult to cope with. Traditional democracy is confronted with new ways of policy making. New practices include multi-level governance, public?–?private partnerships and citizen participation. Central government and parliamentary control have to adapt to such practices. This article studies institutional tensions in two cases of spatial investment, using representative and participatory democracy as models of political regime and policy implementation. The analysis also links governance to characteristics of space. The authors make recommendations to combine ‘representative’ and ‘participatory’ elements of governance in a way that reduces institutional tensions in processes of spatial investment.