human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge groups authors who co-authored the same paper.

Details of the hypergraph:
Center hyperedge (induced by source paper "On the average Steiner distance of graphs with prescribed properties"):
  Abstract: Abstract   The average  n -distance of a connected graph  G ,  μ   n  ( G ), is the average of the Steiner distances of all  n -sets of vertices of  G . In this paper, we give bounds on  μ   n   for two-connected graphs and for  k -chromatic graphs. Moreover, we show that  μ   n  ( G ) does not depend on the  n -diameter of  G .

Includes members:
  Member "Average distance and domination number":
    also connected through other hyperedges:
      (none)

Question: Please tell me which research area the co-authored paper (i.e., the source paper of the center hyperedge) belongs to. The 4 classes are: Computer science, Mathematics, Engineering, Economics, Psychology, Business. Directly output the class name.

gpt: Mathematics