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: "characterising equilibrium logic and nested logic programs reductions and complexity1 2"
  Abstract: Equilibrium logic is an approach to non-monotonic reasoning that extends the stable-model and answer-set semantics for logic programs. In particular, it includes the general case of nested logic programs, where arbitrary Boolean combinations are permitted in heads and bodies of rules, as special kinds of theories. In this paper, we present polynomial reductions of the main reasoning tasks associated with equilibrium logic and nested logic programs into quantified propositional logic, an extension of classical propositional logic where quantifications over atomic formulas are permitted. Thus, quantified propositional logic is a fragment of second-order logic, and its formulas are usually referred to as quantified Boolean formulas (QBFs). We provide reductions not only for decision problems, but also for the central semantical concepts of equilibrium logic and nested logic programs. In particular, our encodings map a given decision problem into some QBF such that the latter is valid precisely in case the former holds. The basic tasks we deal with here are the consistency problem, brave reasoning and skeptical reasoning. Additionally, we also provide encodings for testing equivalence of theories or programs under different notions of equivalence, viz. ordinary, strong and uniform equivalence. For all considered reasoning tasks, we analyse their computational complexity and give strict complexity bounds. Hereby, our encodings yield upper bounds in a direct manner. Besides this useful feature, our approach has the following benefits: First, our encodings yield a uniform axiomatisation for a variety of problems in a common language. Second, extant solvers for QBFs can be used as back-end inference engines to realise implementations of the encoded task in a rapid prototyping manner. Third, our axiomatisations also allow us to straightforwardly relate equilibrium logic with circumscription.

Connected through hyperedge HE-1 (induced by source paper "structural decompositions of epistemic logic programs"):
  with members:
    - "epistemic logic programs a different world view"
    - "treewidth and counting projected answer sets"
    - "te eth lower bounds for qbfs of bounded treewidth"
    - "splitting epistemic logic programs"
    - "answer set solving with bounded treewidth revisited"
    - "the power of non ground rules in answer set programming"
    - "combining treewidth and backdoors for csp"
    - "clique width and directed width measures for answer set programming"

Connected through hyperedge HE-2 (induced by source paper "on uniform equivalence of epistemic logic programs"):
  with members:
    - "revisiting epistemic specifications"
    - "modularity aspects of disjunctive stable models"
    - "discovering classes of strongly equivalent logic programs"
    - "strong equivalence made easy nested expressions and weight constraints"

Connected through hyperedge HE-3 (induced by source paper "epistemic logic programs a different world view"):
  with members:
    - "revisiting epistemic specifications"
    - "discovering classes of strongly equivalent logic programs"
    - "strong equivalence made easy nested expressions and weight constraints"

Connected through hyperedge HE-4 (induced by source paper "dual normal logic programs the forgotten class"):
  with members:
    - "backdoors to normality for disjunctive logic programs"
    - "team building with answer set programming in the gioia tauro seaport"
    - "trichotomy and dichotomy results on the complexity of reasoning with disjunctive logic programs"
    - "semantical characterizations and complexity of equivalences in answer set programming"
    - "unfolding partiality and disjunctions in stable model semantics"

Connected through hyperedge HE-5 (induced by source paper "strong equivalence of qualitative optimization problems"):
  with members:
    - "the computational complexity of dominance and consistency in cp nets"
    - "semantical characterizations and complexity of equivalences in answer set programming"
    - "cp nets a tool for representing and reasoning with conditional ceteris paribus preference statements"
    - "strong equivalence made easy nested expressions and weight constraints"
    - "stable models and an alternative logic programming paradigm"

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)