On Blocking Coalitions: Linking Mas-Colell with Grodal-Schmeidler-Vind

In this paper we investigate the question of how many coalitions of a given relative size would block a non-Warlasian allocation in large finite economies. It is shown that in finite economies, if a Pareto optimal allocation is bounded away from being Walrasian, then, for any two numbers α, β between 0 and 1, the proportion of blocking coalitions in the set of all coalitions with relative size between α and β, is arbitrarily close to 1/2, as the number of individuals in the economy becomes large.

Cost justification of data compression in Ameritech

American Information Technologies (Ameritech) owns the Bell Operating Companies (BOCs) that provide local telephone service in Illinois, Michigan, Indiana, Ohio, and Wisconsin. Ameritech plans to reduce costs by developing common application systems for the Ameritech BOCs, by reducing duplication of effort, and by deploying common technologies. The deployment of common systems and technologies will result in standard methods and procedures throughout the Ameritech region. One piece of the common technological platform relates to the justification of a standard software package to be used by all BOCs to compress their data base management system segments. Each BOC currently has some method of compressing segments. Because each BOC maintains control over their own software expenditure budgets, justification must be provided as to the benefits of the conversion to some common data compression platform. The costs and savings of the conversion must be quantified to determine what serves the interests of Ameritech best, rather than the interests of an individual BOC. The researcher will discuss and evaluate the alternatives of doing nothing, using the software package licensed on the most computers in Ameritech, using the package used in the most Ameritech BOCs, using the package used to compress the most data bases, and developing the software in-house. The researcher will show that the best alternative for Ameritech would be to choose the software package licensed for the largest number of computers

Dark matter, neutron stars and strange quark matter

We show that self-annihilating neutralino WIMP dark matter accreted onto neutron stars may provide a mechanism to seed compact objects with long-lived lumps of strange quark matter, or strangelets, for WIMP masses above a few GeV. This effect may trigger a conversion of most of the star into a strange star. We use an energy estimate for the long-lived strangelet based on the Fermi gas model combined with the MIT bag model to set a new limit on the possible values of the WIMP mass that can be especially relevant for subdominant species of massive neutralinos.Comment: 5 pages, 2 figures, accepted for publication in Phys. Rev. Let