Directed minimum cost spanning tree problems of a special kind are studied, namely those which show up in considering the problem of connecting units (houses) in mountains with a purifier. For such problems an easy method is described to obtain a minimum cost spanning tree. The related cost...

This paper deals with a new class of multi-choice games, the class of multi-choice total clan games. The structure of the core of a multi-choice clan game is explicitly described. Furthermore, characterizations of multi-choice total clan games are given and bi-monotonic allocation schemes...