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: "querying the guarded fragment"
  Abstract: Evaluating a Boolean conjunctive query Q against a guarded first-order theory F is equivalent to checking whether "F and not Q" is unsatisfiable. This problem is relevant to the areas of database theory and description logic. Since Q may not be guarded, well known results about the decidability, complexity, and finite-model property of the guarded fragment do not obviously carry over to conjunctive query answering over guarded theories, and had been left open in general. By investigating finite guarded bisimilar covers of hypergraphs and relational structures, and by substantially generalising Rosati's finite chase, we prove for guarded theories F and (unions of) conjunctive queries Q that (i) Q is true in each model of F iff Q is true in each finite model of F and (ii) determining whether F implies Q is 2EXPTIME-complete. We further show the following results: (iii) the existence of polynomial-size conformal covers of arbitrary hypergraphs; (iv) a new proof of the finite model property of the clique-guarded fragment; (v) the small model property of the guarded fragment with optimal bounds; (vi) a polynomial-time solution to the canonisation problem modulo guarded bisimulation, which yields (vii) a capturing result for guarded bisimulation invariant PTIME.

Connected through hyperedge HE-1 (induced by source paper "finite open world query answering with number restrictions"):
  with members:
    - "finite query answering in expressive description logics with transitive roles"
    - "finite open world query answering with number restrictions"
    - "data complexity of the two variable fragment with counting quantifiers"

Connected through hyperedge HE-2 (induced by source paper "querying guarded fragments via resolution"):
  with members:
    - "deciding the loosely guarded fragment and querying its horn fragment using resolution"
    - "hypertree decompositions and tractable queries"

Connected through hyperedge HE-3 (induced by source paper "deciding the loosely guarded fragment and querying its horn fragment using resolution"):
  with members:
    - "conjunctive query answering for the description logic shiq"

Connected through hyperedge HE-4 (induced by source paper "model comparison games for horn description logics"):
  with members:
    - "query inseparability for alc ontologies"
    - "a van benthem theorem for fuzzy modal logic"
    - "learning first order definable concepts over structures of small degree"
    - "dichotomies in ontology mediated querying with the guarded fragment"
    - "the data complexity of description logic ontologies"
    - "the complexity of reverse engineering problems for conjunctive queries"
    - "on the expressive power of sub propositional fragments of modal logic"
    - "simulations and bisimulations for coalgebraic modal logics"

Connected through hyperedge HE-5 (induced by source paper "the limits of efficiency for open and closed world query evaluation under guarded tgds"):
  with members:
    - "when is ontology mediated querying efficient"
    - "containment for rule based ontology mediated queries"
    - "semantic acyclicity under constraints"
    - "ontology based data access a study through disjunctive datalog csp and mmsnp"
    - "guarded second order logic spanning trees and network flows"
    - "tractable hypergraph properties for constraint satisfaction and conjunctive queries"

Connected through hyperedge HE-6 (induced by source paper "a more general theory of static approximations for conjunctive queries"):
  with members:
    - "constraint solving via fractional edge covers"
    - "semantic acyclicity under constraints"
    - "general and fractional hypertree decompositions hard and easy cases"
    - "decidability results for the boundedness problem"
    - "beyond hypertree width decomposition methods without decompositions"
    - "hypertree decompositions and tractable queries"

Connected through hyperedge HE-7 (induced by source paper "when can we answer queries using result bounded data interfaces"):
  with members:
    - "finite open world query answering with number restrictions"
    - "finite open world query answering with number restrictions"
    - "data complexity of the two variable fragment with counting quantifiers"

Connected through hyperedge HE-8 (induced by source paper "a new decidable class of tuple generating dependencies the triangularly guarded class"):
  with members:
    - "existential rule languages with finite chase complexity and expressiveness"

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)