摘要：We define a hypergraph by a set of associations which consist of nonexclusive two or
more players. It is a generalization of a graph (or a network) in the sense that an association,
the counterpart of a link in a hypergraph, connects any number of nodes, not simply a pair of
nodes. We characterize the efficient hypergraphs and stable hypergraphs for the linear variable
cost of associations. The efficient hypergraph is either the empty hypergraph or the grand
hypergraph consisting of a single grand association. The stable hypergraph can be a grand
hypergraph, a star hypergraph or a line hypergraph. If a star hypergraph is stable, it must have
a singleton center. Generally, a hypergraph can be underconnected, but cannot be over-
connected.
