We consider a pairwise kidney exchange model. Roth et al. (2005) define priority matchings of the model and introduce a mechanism to derive them. In this paper, we re-examine the priority matching. First, we consider a general priority ordering where multiple patients may hold equal priority. We...

Jehiel (1992) and Friedman and Thisse (1993) show that spatial agglomeration appears in a standard two-stage location price model if symmetric firms collude in prices. We introduce a cost difference between two firms. We show that agglomeration never appears in a collusive equilibrium even when...