Michael Heller, Professor of Property et al here at Columbia (and probably one of the best professors I have ever had) is well known for his accalimed tragedy of the anti-commons theories. Where as the tragedy of the commons can be basbarically boiled down to the premis that rational individuals, acting separately, may collectively over-utilize a scarce resource, the tragedy of the anti commons, for those who have not had the benefit of reading some of Heller's work, boils down to the idea that individuals may under-utilize a resource. For example, if too many different individuals hold patents for various inputs necessary for a certain drug's production, the drug maker may not be able to bargain and acquire every patent that he needs and thus, the drug is not produced.