Regular papers

Dietmar Berwanger and Erich Grädel, Aachen U of Techn., Germany
Fixed point formulae and solitaire games

Arnaud Durand, U Paris XII (Val-de-Marne), France and Miki Hermann, École Polytechnique, France
The inference problem for propositional circumscription of affine formulas is coNP-complete

Manfred Schmidt-Schauß, Frankfurt U, Germany and Jürgen Stuber, LORIA Nancy, France
On the complexity of linear and stratified context matching problems

Oswaldo Terán, Universidad de Los Andes, Venezuela and Bruce Edmonds, Manchester Metropolitan U, UK
Computational complexity of a constraint model-based proof of the envelope of tendencies in a MAS-based simulation model