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: "answering non monotonic queries in relational data exchange"
  Abstract: Relational data exchange is the problem of translating relational data from a#N#source schema into a target schema, according to a specification of the#N#relationship between the source data and the target data. One of the basic#N#issues is how to answer queries that are posed against target data. While#N#consensus has been reached on the definitive semantics for monotonic queries,#N#this issue turned out to be considerably more difficult for non-monotonic#N#queries. Several semantics for non-monotonic queries have been proposed in the#N#past few years. This article proposes a new semantics for non-monotonic#N#queries, called the GCWA*-semantics. It is inspired by semantics from the area#N#of deductive databases. We show that the GCWA*-semantics coincides with the#N#standard open world semantics on monotonic queries, and we further explore the#N#(data) complexity of evaluating non-monotonic queries under the#N#GCWA*-semantics. In particular, we introduce a class of schema mappings for#N#which universal queries can be evaluated under the GCWA*-semantics in#N#polynomial time (data complexity) on the core of the universal solutions.

Connected through hyperedge HE-1 (induced by source paper "on equivalence and cores for incomplete databases in open and closed worlds"):
  with members:
    - "on minimal constraint networks"

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)