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: "ranked enumeration of conjunctive query results"
  Abstract: We investigate the enumeration of top-k answers for conjunctive queries against relational databases according to a given ranking function. The task is to design data structures and algorithms that allow for efficient enumeration after a preprocessing phase. Our main contribution is a novel priority queue based algorithm with near-optimal delay and non-trivial space guarantees that are output sensitive and depend on structure of the query. In particular, we exploit certain desirable properties of ranking functions that frequently occur in practice and degree information in the database instance, allowing for efficient enumeration. We introduce the notion of {\em decomposable} and {\em compatible} ranking functions in conjunction with query decomposition, a property that allows for partial aggregation of tuple scores in order to efficiently enumerate the ranked output. We complement the algorithmic results with lower bounds justifying why certain assumptions about properties of ranking functions are necessary and discuss popular conjectures providing evidence for optimality of enumeration delay guarantees. Our results extend and improve upon a long line of work that has studied ranked enumeration from both theoretical and practical perspective.

Connected through hyperedge HE-1 (induced by source paper "optimal algorithms for ranked enumeration of answers to full conjunctive queries"):
  with members:
    - "any k anytime top k tree pattern retrieval in labeled graphs"
    - "on functional aggregate queries with additive inequalities"
    - "on the enumeration complexity of unions of conjunctive queries"
    - "size bounds and query plans for relational joins"
    - "covers of query results"
    - "constraint solving via fractional edge covers"
    - "answering conjunctive queries under updates"
    - "what do shannon type inequalities submodular width and disjunctive datalog have to do with one another"

Connected through hyperedge HE-2 (induced by source paper "answering unions of conjunctive queries using random access and random order enumeration"):
  with members:
    - "optimal algorithms for ranked enumeration of answers to full conjunctive queries"
    - "on the enumeration complexity of unions of conjunctive queries"
    - "enumeration complexity of conjunctive queries with functional dependencies"
    - "tight hardness for shortest cycles and paths in sparse graphs"
    - "answering ucqs under updates and in the presence of integrity constraints"
    - "powers of tensors and fast matrix multiplication"
    - "popular conjectures imply strong lower bounds for dynamic problems"

Connected through hyperedge HE-3 (induced by source paper "solving linear programs on factorized databases"):
  with members:
    - "general and fractional hypertree decompositions hard and easy cases"
    - "efficient inverse maintenance and faster algorithms for linear programming"
    - "aggregation in probabilistic databases via knowledge compilation"
    - "combining relational algebra sql constraint modelling and local search"
    - "hypertree decompositions and tractable queries"

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)