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: "charting the tractability frontier of certain conjunctive query answering"
  Abstract: An uncertain database is defined as a relational database in which primary keys need not be satisfied. A repair (or possible world) of such database is obtained by selecting a maximal number of tuples without ever selecting two distinct tuples with the same primary key value. For a Boolean query q, the decision problem CERTAINTY(q) takes as input an uncertain database db and asks whether q is satisfied by every repair of db. Our main focus is on acyclic Boolean conjunctive queries without self-join. Previous work has introduced the notion of (directed) attack graph of such queries, and has proved that CERTAINTY(q) is first-order expressible if and only if the attack graph of q is acyclic. The current paper investigates the boundary between tractability and intractability of CERTAINTY(q). We first classify cycles in attack graphs as either weak or strong, and then prove among others the following. If the attack graph of a query q contains a strong cycle, then CERTAINTY(q) is coNP-complete. If the attack graph of q contains no strong cycle and every weak cycle of it is terminal (i.e., no edge leads from a vertex in the cycle to a vertex outside the cycle), then CERTAINTY(q) is in P. We then partially address the only remaining open case, i.e., when the attack graph contains some nonterminal cycle and no strong cycle. Finally, we establish a relationship between the complexities of CERTAINTY(q) and evaluating q on probabilistic databases.

Connected through hyperedge HE-1 (induced by source paper "a sat based system for consistent query answering"):
  with members:
    - "holoclean holistic data repairs with probabilistic inference"
    - "consistent query answering via asp from different perspectives theory and practice"
    - "answer sets for consistent query answering in inconsistent databases"

Connected through hyperedge HE-2 (induced by source paper "consistent answers of conjunctive queries on graphs"):
  with members:
    - "a trichotomy in the data complexity of certain query answering for conjunctive queries"
    - "a dichotomy on the complexity of consistent query answering for atoms with simple keys"
    - "minimal change integrity maintenance using tuple deletions"

Connected through hyperedge HE-3 (induced by source paper "a trichotomy in the data complexity of certain query answering for conjunctive queries"):
  with members:
    - "a dichotomy on the complexity of consistent query answering for atoms with simple keys"

Connected through hyperedge HE-4 (induced by source paper "tractable vs intractable cases of matching dependencies for query answering under entity resolution"):
  with members:
    - "a dichotomy on the complexity of consistent query answering for atoms with simple keys"
    - "data cleaning and query answering with matching dependencies and matching functions"

Connected through hyperedge HE-5 (induced by source paper "a dichotomy on the complexity of consistent query answering for atoms with simple keys"):
  with members:
    - "minimal change integrity maintenance using tuple deletions"

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)