human: Given a node-centered hypergraph: <hypergraph>, where nodes represent papers and hyperedges represent sets of papers co-cited by a source paper.

Details of the hypergraph:
Center node: "semantically correct query answers in the presence of null values"
  Abstract: For several reasons a database may not satisfy a given set of integrity constraints(ICs), but most likely most of the information in it is still consistent with those ICs; and could be retrieved when queries are answered. Consistent answers to queries wrt a set of ICs have been characterized as answers that can be obtained from every possible minimally repaired consistent version of the original database. In this paper we consider databases that contain null values and are also repaired, if necessary, using null values. For this purpose, we propose first a precise semantics for IC satisfaction in a database with null values that is compatible with the way null values are treated in commercial database management systems. Next, a precise notion of repair is introduced that privileges the introduction of null values when repairing foreign key constraints, in such a way that these new values do not create an infinite cycle of new inconsistencies. Finally, we analyze how to specify this kind of repairs of a database that contains null values using disjunctive logic programs with stable model semantics.

Connected through hyperedge HE-1 (induced by source paper "consistency and trust in peer data exchange systems"):
  with members:
    - "relational theories with null values and non herbrand stable models"
    - "why would you trust b"
    - "the dlv system for knowledge representation and reasoning"
    - "answer sets for consistent query answering in inconsistent databases"
    - "minimal change integrity maintenance using tuple deletions"

Connected through hyperedge HE-2 (induced by source paper "from causes for database queries to repairs and model based diagnosis and back"):
  with members:
    - "causes for query answers from databases datalog abduction and view updates the presence of integrity constraints"
    - "query answer causality in databases abductive diagnosis and view updates"
    - "unifying causality diagnosis repairs and view updates in databases"
    - "causality in databases the diagnosis and repair connections"
    - "achieving data privacy through secrecy views and null based virtual updates"
    - "the complexity of causality and responsibility for query answers and non answers"
    - "approximate model based diagnosis using greedy stochastic search"
    - "prioritized repairing and consistent query answering in relational databases"

Connected through hyperedge HE-3 (induced by source paper "achieving data privacy through secrecy views and null based virtual updates"):
  with members:
    - "the dlv system for knowledge representation and reasoning"
    - "minimal change integrity maintenance using tuple deletions"

Connected through hyperedge HE-4 (induced by source paper "active integrity constraints and revision programming"):
  with members:
    - "answer sets for consistent query answering in inconsistent databases"

Question: Please tell me which class the center node belongs to. The 40 classes are: cs.NA(Numerical Analysis), cs.MM(Multimedia), cs.LO(Logic in Computer Science), cs.CY(Computers and Society), cs.CR(Cryptography and Security), cs.DC(Distributed, Parallel, and Cluster Computing), cs.HC(Human-Computer Interaction), cs.CE(Computational Engineering, Finance, and Science), cs.NI(Networking and Internet Architecture), cs.CC(Computational Complexity), cs.AI(Artificial Intelligence), cs.MA(Multiagent Systems), cs.GL(General Literature), cs.NE(Neural and Evolutionary Computing), cs.SC(Symbolic Computation), cs.AR(Hardware Architecture), cs.CV(Computer Vision and Pattern Recognition), cs.GR(Graphics), cs.ET(Emerging Technologies), cs.SY(Systems and Control), cs.CG(Computational Geometry), cs.OH(Other Computer Science), cs.PL(Programming Languages), cs.SE(Software Engineering), cs.LG(Machine Learning), cs.SD(Sound), cs.SI(Social and Information Networks), cs.RO(Robotics), cs.IT(Information Theory), cs.PF(Performance), cs.CL(Computation and Language), cs.IR(Information Retrieval), cs.MS(Mathematical Software), cs.FL(Formal Languages and Automata Theory), cs.DS(Data Structures and Algorithms), cs.OS(Operating Systems), cs.GT(Computer Science and Game Theory), cs.DB(Databases), cs.DL(Digital Libraries), cs.DM(Discrete Mathematics). Directly output the class name.

gpt: cs.DB(Databases)