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: "Finding equilibria in games of no chance"
  Abstract: We consider finding maximin strategies and equilibria of explicitly given extensive form games with imperfect information but with no moves of chance. We show that a maximin pure strategy for a twoplayer game with perfect recall and no moves of chance can be found in time linear in the size of the game tree and that all pure Nash equilibrium outcomes of a two-player general-sum game with perfect recall and no moves of chance can be enumerated in time linear in the size of the game tree. We also show that finding an optimal behavior strategy for a one-player game of no chance without perfect recall and determining whether an equilibrium in behavior strategies exists in a two-player zero-sum game of no chance without perfect recall are both NP-hard.

Connected through hyperedge HE-1 (induced by source paper "Extensive-Form Correlated Equilibrium: Definition and Computational Complexity"):
  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