Before revision: Given two point sets S and T, we first study the many-to-many matching with demands (MMD) problem , where each point of one set must be matched to at least a given number of the points of the other set .
After revision: Given two point sets S and T, we first study the many-to-many matching with demands (MMD) problem is the problem of finding a minimum-cost many-to-many matching between S and T such that each point of one set must be matched to at least a given number of the points of the other set .