Scheduling with Opting Out: Improving upon Random Priority

In a scheduling problem where agents can opt out, we show that the familiar Random Priority (RP) a rule can be improved upon by another mechanism dubbed Probabilistic Serial (PS). Both mechanisms are nonmanipulable in a strong sense, but the latter is Pareto superior to the former and serves a larger (expected number of agents. The PS equilibrium outcome is easier to compute than the RP outcome; on the other hand RP is easier to implement than PS. We show that the improvement of PS over RP is significant but small: at most a couple of percentage points in the relative welfare gain and the relative difference in quantity served. We conjecture that the latter never exceeds 8.33 %. Both gains vanish when the number of agents is large.

Low frequency dispersive estimates for the wave equation in higher dimensions

We prove dispersive estimates at low frequency in dimensions n greater or equal to 4 for the wave equation for a very large class of real-valued potentials, provided the zero is neither an eigenvalue nor a resonance.Comment: 10 page

Consistent bilateral assignment

In the bilateral assignment problem, source a holds the amount ra of resource of type a, while sink i must receive the total amount xi of the various resources. We look for assignment rules meeting the powerful separability property known as Consistency: “every subassignment of a fair assignment is fair”. They are essentially those rules selecting the feasible flow minimizing the sum ∑i,aW(yia), where W is smooth and strictly convex

Microfinance investment vehicles in Sub-Saharan Africa: constraints and potentials

This paper sheds the light on the potential and constraints of possible interactions between Microfinance Investment Vehicles (MIVs) and the two main African Microfinance models namely the cooperative model, well developed in West Africa, and the commercial model, found in East Africa. We assess if both parties can gain from those interactions. We argue that given the significant funding needs of Microfinance institutions (MFIs) in that part of the world, in particular with regards to equity investments and capacity building, the African microfinance sector requires resources that can only be provided with the contest of private investors. In this respect, provided some conditions are met, for instance the presence in these vehicles of Development financial institutions (DFIs) that play the role of catalysts by initiating investments and taking risks that private investors would not dare taking; MIVs could be suitable for the financing of the rural and the micro-enterprises segments which are still seen as highly risky investments. Those segments require more volumes and longer term funding, but they have a great potential positive effect on Microfinance recipients and more generally on the economies they live in. In the MIVs’ perspective, due to excessive risks’ perception, the interest for the African microfinance still remains limited to date; however, the increasing demand for socially responsible investments and the needs for Microfinance investment portfolios’ diversification will push those vehicles to commit more and more for investments in that part of the world.Microfinance, Microfinance investment vehicles, Sub-Saharan Africa

Minimizing the Worst Slowdown: Off-Line and On-Line

Minimizing the slowdown (expected sojourn time divided by job size) is a key concern of fairness in scheduling and queuing problems where job sizes are very heterogeneous. We look for protocols (service disciplines) capping the worst slowdown (called here liability) a job may face no matter how large (or small) the other jobs are. In the scheduling problem (all jobs released at the same time), allowing the server to randomize the order of service cuts almost in half the liability profiles feasible under deterministic protocols. The same statement holds if cash transfers are feasible and users have linear waiting costs.

Three Solutions to a Simple Commons Problem

We compare the equity and incentive properties of three efficient solutions to a simple problem of cooperative production with binary demands for a homogeneous service, when marginal cost is either monotonically increasing or monotonically decreasing. The solutions are the familiar competitive equilibrium with equal incomes. The Shapley value of the stand alone cooperative game, and the virtual price solution, applying the egalitarian equivalence idea to this particular model.