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: "Coloring intersection graphs of x-monotone curves in the plane"
  Abstract: A class of graphs G is ?-bounded if the chromatic number of the graphs in G is bounded by some function of their clique number. We show that the class of intersection graphs of simple families of x-monotone curves in the plane intersecting a vertical line is ?-bounded. As a corollary, we show that the class of intersection graphs of rays in the plane is ?-bounded, and the class of intersection graphs of unit segments in the plane is ?-bounded.

Connected through hyperedge HE-1 (induced by source paper "Triangle-free intersection graphs of line segments with large chromatic number"):
  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