human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge groups authors who co-authored the same paper.

Details of the hypergraph:
Center hyperedge (induced by source paper "A foundation of CODD's relational maybe-operations"):
  Abstract: Database relations which possibly contain maybe-tuples and null values of type “value at present unknown” are studied. Maybe-tuples and null values are formally interpreted by our notion of  representation , which uses classical notions of predicate logic, elaborates Codd's proposal of maybe-tuples, and adopts Reiter's concept of a closed world. Precise notions of  information content  and  redundancy , associated with our notion of representation, are investigated.  Extensions of the relational algebra  to relations with maybe-tuples and null values are proposed. Our extensions are essentially Codd's, with some modifications. It is proved that these extensions have natural properties which are formally stated as being  adequate  and  restricted .  By the treatment of difference and division, our formal framework can be used even for operations that require “negative information.” Finally, extensions of  update operations  are discussed.

Includes members:
  Member "Logic and databases: a 20 year retrospective":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "Managing requirements inconsistency with development goal monitors")
  Member "Relational database: a practical foundation for productivity":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "Query by example")

Question: Please tell me which research area the co-authored paper (i.e., the source paper of the center hyperedge) belongs to. The 4 classes are: Computer science, Mathematics, Engineering, Economics, Psychology, Business. Directly output the class name.

gpt: Computer science