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: "on the complexity of existential positive queries"
  Abstract: We systematically investigate the complexity of model checking the existential positive fragment of first-order logic. In particular, for a set of existential positive sentences, we consider model checking where the sentence is restricted to fall into the set; a natural question is then to classify which sentence sets are tractable and which are intractable. With respect to fixed-parameter tractability, we give a general theorem that reduces this classification question to the corresponding question for primitive positive logic, for a variety of representations of structures. This general theorem allows us to deduce that an existential positive sentence set having bounded arity is fixed-parameter tractable if and only if each sentence is equivalent to one in bounded-variable logic. We then use the lens of classical complexity to study these fixed-parameter tractable sentence sets. We show that such a set can be NP-complete, and consider the length needed by a translation from sentences in such a set to bounded-variable logic; we prove superpolynomial lower bounds on this length using the theory of compilability, obtaining an interesting type of formula size lower bound. Overall, the tools, concepts, and results of this article set the stage for the future consideration of the complexity of model checking on more expressive logics.

Connected through hyperedge HE-1 (induced by source paper "when is ontology mediated querying efficient"):
  with members:
    - "the complexity of ontology based data access with owl 2 ql and bounded treewidth queries"
    - "semantic acyclicity under constraints"
    - "ontology mediated queries combined complexity and succinctness of rewritings via circuit complexity"
    - "ontology based data access a study through disjunctive datalog csp and mmsnp"
    - "the dl lite family and relations"

Connected through hyperedge HE-2 (induced by source paper "the parameterized space complexity of model checking bounded variable first order logic"):
  with members:
    - "computing hitting set kernels by ac 0 circuits"
    - "fast parallel fixed parameter algorithms via color coding"
    - "one hierarchy spawns another graph deconstructions and the complexity classification of conjunctive queries"
    - "deciding first order properties of nowhere dense graphs"
    - "bounds on monotone switching networks for directed connectivity"
    - "fixed parameter tractability definability and model checking"

Connected through hyperedge HE-3 (induced by source paper "counting answers to existential positive queries a complexity classification"):
  with members:
    - "the tractability frontier of graph like first order query sets"
    - "a trichotomy in the complexity of counting answers to conjunctive queries"
    - "structural tractability of counting of solutions to conjunctive queries"
    - "one hierarchy spawns another graph deconstructions and the complexity classification of conjunctive queries"
    - "tractable hypergraph properties for constraint satisfaction and conjunctive queries"

Connected through hyperedge HE-4 (induced by source paper "the logic of counting query answers"):
  with members:
    - "counting answers to existential positive queries a complexity classification"
    - "the tractability frontier of graph like first order query sets"
    - "a trichotomy in the complexity of counting answers to conjunctive queries"
    - "structural tractability of counting of solutions to conjunctive queries"
    - "one hierarchy spawns another graph deconstructions and the complexity classification of conjunctive queries"
    - "tree width for first order formulae"

Connected through hyperedge HE-5 (induced by source paper "the logic of counting query answers a study via existential positive queries"):
  with members:
    - "a trichotomy in the complexity of counting answers to conjunctive queries"
    - "structural tractability of counting of solutions to conjunctive queries"

Connected through hyperedge HE-6 (induced by source paper "the tractability frontier of graph like first order query sets"):
  with members:
    - "counting answers to existential positive queries a complexity classification"
    - "complexity of counting subgraphs only the boundedness of the vertex cover number counts"
    - "a trichotomy in the complexity of counting answers to conjunctive queries"
    - "structural tractability of counting of solutions to conjunctive queries"
    - "one hierarchy spawns another graph deconstructions and the complexity classification of conjunctive queries"
    - "the fine classification of conjunctive queries and parameterized logarithmic space complexity"
    - "tree width for first order formulae"

Connected through hyperedge HE-7 (induced by source paper "structural tractability of counting of solutions to conjunctive queries"):
  with members:
    - "constraint solving via fractional edge covers"
    - "structural tractability of enumerating csp solutions"
    - "the complexity of weighted counting for acyclic conjunctive queries"
    - "beyond hypertree width decomposition methods without decompositions"
    - "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.LO(Logic in Computer Science)