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: "An example of hierarchical design and proof"
  Abstract: Hierarchical programming is being increasingly recognized as helpful in the construction of large programs. Users of hierarchical techniques claim or predict substantial increases in productivity and in the reliability of the programs produced. In this paper we describe a formal method for hierarchical program specification, implementation, and proof. We apply this method to a significant list processing problem and also discuss a number of extensions to current programming languages that ease hierarchical program design and proof.

Connected through hyperedge HE-1 (induced by source paper "Proof techniques for hierarchically structured programs"):
  with members:
    - "A specification technique based on predicate transformers"

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: Computer science