Collective Rationality in Graph Aggregation
Ulle Endriss, Umberto Grandi

Abstract:
Suppose a number of agents each provide us with a directed graph 
over a common set of vertices. Graph aggregation is the problem 
of computing a single “collective” graph that best represents the 
information inherent in this profile of individual graphs. We consider 
this aggregation problem from the point of view of social choice 
theory and ask what properties shared by the individual graphs 
will transfer to the graph computed by a given aggregation 
procedure. Our main result is a general impossibility theorem that 
applies to a wide range of graph properties.