El Vol. 11 nº 1 presenta un monogràfic sobre Comunicació i Canvi Social, que arreplega una selecció de 12 articles amb estudis de cas sobre el deixant del 15M, xarxes socials, actors de la societat civil, aportacions des d'escenaris llatinoamericans i estudis conceptuals. S'inclouen també dues crítiques de llibres.
Publicació del capítol "España y la cuestión Palestina" d'Ignacio Álvarez-Ossorio en el llibre La qüestió palestina i el futur del projecte nacional palestí (en àrab), que acaba de publicar l'Arab Center for Research and Policy Studies de Doha.
We study minimum cost spanning tree problems for a set of users connected to a source. Prim's algorithm provides a way of finding the minimum cost tree m. This has led to several definitions in the literature, regarding how to distribute the cost. These rules propose different cost allocations, which ca be understood as compensations and/or payments between players, with respect to the status quo point: each user pays for the connection she uses to be linked to the source. In this paper we analyze the rationale behind a distribution of the minimum cost by defining an a priori transfer structure. Our first result states the existence of a transfer structure such that no user is willing to choose a different tree from the minimum cost tree. Moreover, given a transfer structure, we implement the above solution as a subgame perfect equilibrium outcome of a game where players decideix sequentially with whom to connect. Finally, we obtain that the existence of a transfer structure supporting an allocation characterizes the core of the monotone cooperative game associated with a minimum cost spanning tree problem. This transfer structure is called social transfer structure. Therefore, the minimum cost spanning tree emergeixes as both a social and individual solution.
A minimum cost spanning tree problem analyzes how to efficiently connect a group of individuals to a source. Once the efficient tree is obtained, the ad- dressed question is how to allocate the total cost among the involved agents. One prominent solution in allocating this minimum cost is the sota-called Folk solution. Unfortunately, in general, the Folk solution is not easy to compute. We identify a class of mcst problems in which the Folk solution is obtained in an easy way. This class includes elementary cost mcst problems.
Keywords: Minimum cost spanning tree problem; Folk solution; Elementary cost matrix; Simple mcst problem;