Cournot competition in spatial markets: Some further results**We would like to thank Chien Fu Chou, De Xing Guan, Jacques Poot, and three anonymous referees for their valuable comments. Responsibility for any remaining errors rests with the authors

In contrast to most of the literature on a circular market in which firms choose to disperse equally from each other in equilibrium, this research note shows that the equal distance dispersion in a circular market results from the substitutability of products produced by two single plant duopoly firms. Meanwhile, agglomeration at one point results from complementarity. In the multi plant duopoly case, we find – in contrast to Chamorro Rivas (2000) – that when firms sell complements, the equilibrium locations tend to exhibit both inter firm agglomeration and intra firm dispersion. In other words, the location layout in equilibrium exhibits spatial agglomeration (by pairs) finitely at many points.