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: "Brooks' Theorem via the Alon-Tarsi Theorem"
  Abstract: We give a proof of Brooks' Theorem and its choosability extension based on the Alon-Tarsi Theorem; this also shows that Brooks' Theorem remains valid in a more general game coloring setting.

Connected through hyperedge HE-1 (induced by source paper "Flexible color lists in Alon and Tarsi's theorem, and time scheduling with unreliable participants."):
  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