We consider an extension of minimum cost spanning tree (mcst) problems in which some agents do not need to be connected to the source, but might reduce the cost of others to do so. Even if the cost usually cannot be computed in polynomial time, we extend the characterization of the Kar solution...

We study cost sharing problems where gains from cooperation can come from the presence of other agents, such as when agents share their technologies. A simple model is built, where economies of scale are eliminated in order to study this effect. We use as the key axiom the property that, if an...

Minimum cost spanning tree (mcst) problems try to connect agents efficiently to a source when agents are located at different points in space and the cost of using an edge is fixed. We introduce a new cost sharing solution that always selects a point in the core and that is more responsive to...