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 "Higher-order orderings for normal rewriting"):
  Abstract: We extend the termination proof methods based on reduction orderings to higher-order rewriting systems a la Nipkow using higher-order pattern matching for firing rules, and accommodate for any use of eta, as a reduction, as an expansion or as an equation. As a main novelty, we provide with a mechanism for transforming any reduction ordering including beta-reduction, such as the higher-order recursive path ordering, into a reduction ordering for proving termination of rewriting a la Nipkow. Non-trivial examples are carried out.

Includes members:
  Member "Polymorphic higher-order recursive path orderings":
    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