Consistent enlargements of the core in roommate problems

Abstract

In this paper, we study consistent enlargement of a solution. By computing it, one actually evaluates the extent to which the solution would have to be expanded in order to be well-defined and consistent. We show that the union of stable matchings and the matching recommended by a single-valued, well-defined, individually rational, and consistent solution is a minimal consistent enlargement of the core. Although individual rationality is sufficient it is not a necessity. Next, we show that for any fixed order on the set of agents in the society, the union of stable matchings and the serial dictatorship matching is a minimal consistent enlargement of the core.