We study the stability and the stability index of the meet game form defined on a meet semilattice. Given any active coalition structure, we show that the stability index relative to the equilibrium, to the beta core and to the exact core is a function of the Nakamura number, the depth of the...

In this paper we present the notions of median useful for the aggregation of preferences and, more generally, in problems of consensus. After the introduction on the general notion of median, the first section studies the median relations of a profile of arbitrary or particular (tournaments,...