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: "Geodesic Spanners on Polyhedral Surfaces"
  Abstract: In this paper we consider the problem of efficiently constructing geodesic t-spanners. We consider finding sparse spanners on the surface of a 3 dimensional polyhedron allowing for steiner vertices. If Steiner vertices are not allowed, then we establish lower bounds on the maximum node degree, depending on the spanning ratio t and also the total number of vertices of the polyhedron surface. We also consider the case of the surface of a convex polytope $\mathcal P $ with V vertices. Using its vertex set P and Steiner points, we can construct a t-spanner with a constant degree and weight O(MST(U)), where MST(U) is the minimum spanning tree on the set U of vertices on convex polytope.

Connected through hyperedge HE-1 (induced by source paper "On the hardness of approximating spanners"):
  with members:
    - "A fast parametric maximum flow algorithm and applications"

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