We establish that the fraction of preference profiles for which the random serial dictatorship allocation is ordinally efficient vanishes for allocation problems with many object types. We consider also a probabilistic setting where in expectation agents have moderately similar preferences...

This paper examines a model of duopoly firms selling to an exogenously formed buyer group consisting of members with heterogeneous preferences. Two research questions are addressed: (1) when is it optimal for a buyer group to commit to exclusive purchase from a single seller, and (2) how does...