human: Given a node-centered hypergraph: <hypergraph>, where nodes represent authors and hyperedges represent groups of authors who co-authored the same paper.

Details of the hypergraph:
Center node: "Well-covered graphs without cycles of lengths 4, 5 and 6"
  Abstract: A graph G is well-covered if all its maximal independent sets are of the same cardinality. Assume that a weight function w is defined on its vertices. Then G is w -well-covered if all maximal independent sets are of the same weight, where a weight of a set is the sum of weights of its elements. For every graph G , the set of weight functions w such that G is w -well-covered is a vector space. Given an input graph G without cycles of lengths 4, 5, and 6, we characterize polynomially the vector space of weight functions w for which G is w -well-covered.Let B be an induced complete bipartite subgraph of G on vertex sets of bipartition B X and B Y . Assume that there exists an independent set S such that each of S ? B X and S ? B Y is a maximal independent set of G . Then B is a generating subgraph of G , and it produces the restriction w ( B X ) = w ( B Y ) . It is easy to see that for every weight function w , if G is w -well-covered, then the above restriction is satisfied.In the special case, where B X = { x } and B Y = { y } , we say that x y is a relating edge. Recognizing relating edges and generating subgraphs is an NP-complete problem. However, we provide a polynomial algorithm for recognizing generating subgraphs of an input graph without cycles of lengths 5, 6 and 7. We also present a polynomial algorithm for recognizing relating edges in an input graph without cycles of lengths 5 and 6.

Connected through hyperedge HE-1 (induced by source paper "On relating edges in graphs without cycles of length 4"):
  with members:
    (none)

Question: Please tell me which research area the center author belongs to. The 4 classes are: Computer science, Mathematics, Engineering, Economics, Psychology, Business. Directly output the class name.

gpt: Mathematics