Minimum cost spanning tree problems with groups

We study minimum cost spanning tree problems with groups. We assume that agents are located in different villages, cities, etc. The groups are the agents of the same village. We introduce a rule for dividing the cost of connecting all agents to the source among the agents taking into account the group structure. We characterize this rule with several desirable properties. We prove that this rule coincides with the Owen value of the TU game associated with the irreducible matrix.