Restabilizing matching markets at senior level

Abstract We study, in many-to-one matching markets, the restabilization process of a group-stable matching disrupted by a change in the population. If firms are not allowed to fire workers, the market always reaches stability again only if the disruption is due to the opening of positions by firms, or the retirement of workers. This is shown by designing an algorithm which always leads to a group-stable matching. The algorithm mimics markets where firms make offers and workers accept the offer of their favorite firm. If firms are allowed to fire workers, we construct another algorithm which produces a group-stable matching when the disruption is due to the entrance of workers or the closure of positions. In this algorithm, unemployed workers make offers to firms. In both cases of disruption, we require firms to have q - substitutable preferences.