We develop a theory of price discrimination in many-to-many matching markets in which agents’ preferences are vertically and horizontally differentiated. The optimal plans induce negative assortative matching at the margin: agents with a low value for interacting with other agents are included...

A frequently heard explanation for the underdeveloped metro system in Rome is the following one: If we tried to build a new metro line, it would probably be stopped by archeological finds that are too valuable to destroy, so the investment would be wasted. This statement, which seems...