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: "The Programming Language Aspects of ThingLab, a Constraint-Oriented Simulation Laboratory"
  Abstract: The programming language aspects of a graphic simulation laboratory named ThingLab are presented. The design and implementation of ThingLab are extensions to Smalltalk. In ThingLab,  constraints  are used to specify the relations that must hold among the parts of the simulation. The system is object-oriented and employs  inheritance  and  part-whole  hierarchies to describe the structure of a simulation. An interactive, graphic user interface is provided that allows the user to view and edit a simulation.

Connected through hyperedge HE-1 (induced by source paper "Constraint-Based Automatic Placement for Scene Composition."):
  with members:
    (none)

Connected through hyperedge HE-2 (induced by source paper "An overview of KRL, a Knowledge Representation Language"):
  with members:
    - "BORIS -- An Experiment in In-Depth Understanding of Narratives."
    - "MULTI - a LISP based multiprocessing system"
    - "The tractability of subsumption in frame-based description languages"
    - "GUS, a frame-driven dialog system"
    - "Six topics in search of a parser: an overview of AI language research"
    - "The prolog phenomenon"
    - "A knowledge-based application definition system"

Connected through hyperedge HE-3 (induced by source paper "Garnet: comprehensive support for graphical, highly interactive user interfaces"):
  with members:
    - "Forms/3: A first-order visual language to explore the boundaries of the spreadsheet paradigm"
    - "Workspaces: an architecture for editing collections of objects"
    - "COLLAGEN: A Collaboration Manager for Software Interface Agents"
    - "A software model and specification language for non-WIMP user interfaces"
    - "The Rendezvous architecture and language for constructing multiuser applications"

Connected through hyperedge HE-4 (induced by source paper "Ownership types for flexible alias protection"):
  with members:
    - "Object-Oriented Design Pattern: Access Protector."

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