Improving Fairness in Nonwasteful Matching with Hierarchical Regional Minimum Quotas

This paper considers matching problems with hierarchical regional minimum quotas. Although such quotas are relevant in many real-world settings, it is known that nonwastefulness and fairness (which compose stability) are incompatible when minimum quotas are imposed. We develop a new strategy-proof nonwasteful mechanism called Adaptive Deferred Acceptance with Regional minimum Quotas (ADA-RQ), which is fairer than an existing nonwasteful mechanism called Multi-Stage DA with Regional minimum Quotas (MSDA-RQ).