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: "Functions operating on multivariate distribution and survival functions-With applications to classical mean-values and to copulas"
  Abstract: Functions operating on multivariate distribution and survival functions are characterized, based on a theorem of Morillas, for which a new proof is presented. These results are applied to determine those classical mean values on [0,1]^n which are distribution functions of probability measures on [0,1]^n. As it turns out, the arithmetic mean plays a universal role for the characterization of distribution as well as survival functions. Another consequence is a far reaching generalization of Kimberling's theorem, tightly connected to Archimedean copulas.

Connected through hyperedge HE-1 (induced by source paper "Monotonicity properties of multivariate distribution and survival functions - With an application to Lévy-frailty copulas"):
  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