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 "Level 5/2 of the Straubing-Thérien Hierarchy for Two-Letter Alphabets"):
  Abstract: We prove an effective characterization of level 5/2 of the Straubing-Therien hierarchy for the restricted case of languages defined over a two-letter alphabet.

Includes members:
  Member "Languages of Dot-Depth 3/2":
    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