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: "extremal problems in logic programming and stable model computation"
  Abstract: We study the following problem: given a class of logic programs C, determine the maximum number of stable models of a program from C. We establish the maximum for the class of all logic programs with at most n clauses, and for the class of all logic programs of size at most n. We also characterize the programs for which the maxima are attained. We obtain similar results for the class of all disjunctive logic programs with at most n clauses, each of length at most m, and for the class of all disjunctive logic programs of size at most n. Our results on logic programs have direct implication for the design of algorithms to compute stable models. Several such algorithms, similar in spirit to the Davis-Putnam procedure, are described in the paper. Our results imply that there is an algorithm that finds all stable models of a program with n clauses after considering the search space of size O(3^{n/3}) in the worst case. Our results also provide some insights into the question of representability of families of sets as families of stable models of logic programs.

Connected through hyperedge HE-1 (induced by source paper "about epistemic negation and world views in epistemic logic programs"):
  with members:
    - "splitting epistemic logic programs"
    - "query answering in resource based answer set semantics"
    - "revisiting epistemic specifications"
    - "xsb extending prolog with tabled logic programming"
    - "normal forms for answer sets programming"
    - "on the existence of stable models of non stratified logic programs"
    - "transformation based bottom up computation of the well founded model"

Connected through hyperedge HE-2 (induced by source paper "characterizing and computing stable models of logic programs the non stratified case"):
  with members:
    - "stable models and an alternative logic programming paradigm"

Connected through hyperedge HE-3 (induced by source paper "automated verification of weak equivalence within the smodels system"):
  with members:
    - "the dlv system for knowledge representation and reasoning"
    - "unfolding partiality and disjunctions in stable model semantics"
    - "strong equivalence made easy nested expressions and weight constraints"
    - "extending the stable model semantics with more expressive rules"
    - "stable models and an alternative logic programming paradigm"

Connected through hyperedge HE-4 (induced by source paper "computing stable models worst case performance estimates"):
  with members:
    - "on the problem of computing the well founded semantics"
    - "fixed parameter complexity of semantics for logic programs"
    - "computing large and small stable models"
    - "dlv a system for declarative problem solving"

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)