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: "Towards imperative modules: reasoning about invariants and sharing of mutable state"
  Abstract: Imperative and object-oriented programs make ubiquitous use of shared mutable objects. Updating a shared object can and often does transgress a boundary that was supposed to be established using static constructs such as a class with private fields. This paper shows how auxiliary fields can be used to express two state-dependent encapsulation disciplines: ownership, a kind of separation, and local co-dependence, a kind of sharing. A methodology is given for specification and modular verification of encapsulated object invariants and shown sound for a class-based language.

Connected through hyperedge HE-1 (induced by source paper "Separation and information hiding"):
  with members:
    - "A local shape analysis based on separation logic"
    - "Secure the clones: static enforcement of policies for secure object copying"

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