Equilibrium uniqueness with perfect complements

Eilon Solan and Nicolas Vieille

It is sometimes the case that some economic goods are perfect complements to some agents, but not to all agents. Here we prove that the equilibrium allocations are at most unique under minimal conditions on the demand functions. In addition, we provide somewhat stringent conditions under which equilibrium prices do exist, discuss a few necessary conditions for existence, and a few examples where equilibrium prices fail to exist.