Assigning tasks to pairs

We study the problem of an organization that has a large number of potential tasks and has to choose which tasks to handle and which pair of experts should be assigned to each of them. We propose a mechanism that generates a Pareto-efficient assignment in the weak core and is group strategy-proof. The assignment rule generated by this mechanism is characterized by four axioms: Pareto-efficiency, the Weak Core property, Restricted Maskin Monotonicity and Invariance with respect to Deleted Links. The last two axioms are invariance properties with respect to specific preference changes.