Resumen de An axiomatic approach in minimum cost spanning tree problems with groups

Gustavo Bergantiños Cid , María Gómez Rúa

• We study minimum cost spanning tree problems with groups, where agents are located in di¤erent villages, cities, etc. The groups are the agents of the same village. In Bergantiños and Gómez-Rúa (2010, Economic Theory) we de…ne the rule F as the Owen value of the ir- reducible game with groups and we prove that F generalizes the folk rule of minimum cost spanning tree problems. Bergantiños and Vidal- Puga (2007, Journal of Economic Theory) give two characterizations of the folk rule. In the …rst one they characterize it as the unique rule satisfying cost monotonicity, population monotonicity and equal share of extra costs. In the second characterization of the folk rule they replace cost monotonicity by independence of irrelevant trees and population monotonicity by separability. In this paper we extend such characterizations to our setting. Some of the properties are the same (cost monotonicity and independence of irrelevant trees) and the other need to be adapted. In general, we do it by claiming the prop- erty twice: once among the groups and the other among the agents inside the same group.