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: "backdoors to normality for disjunctive logic programs"
  Abstract: Over the last two decades, propositional satisfiability (SAT) has become one of the most successful and widely applied techniques for the solution of NP-complete problems. The aim of this paper is to investigate theoretically how Sat can be utilized for the efficient solution of problems that are harder than NP or co-NP. In particular, we consider the fundamental reasoning problems in propositional disjunctive answer set programming (ASP), Brave Reasoning and Skeptical Reasoning, which ask whether a given atom is contained in at least one or in all answer sets, respectively. Both problems are located at the second level of the Polynomial Hierarchy and thus assumed to be harder than NP or co-NP. One cannot transform these two reasoning problems into SAT in polynomial time, unless the Polynomial Hierarchy collapses. We show that certain structural aspects of disjunctive logic programs can be utilized to break through this complexity barrier, using new techniques from Parameterized Complexity. In particular, we exhibit transformations from Brave and Skeptical Reasoning to SAT that run in time O(2^k n^2) where k is a structural parameter of the instance and n the input size. In other words, the reduction is fixed-parameter tractable for parameter k. As the parameter k we take the size of a smallest backdoor with respect to the class of normal (i.e., disjunction-free) programs. Such a backdoor is a set of atoms that when deleted makes the program normal. In consequence, the combinatorial explosion, which is expected when transforming a problem from the second level of the Polynomial Hierarchy to the first level, can now be confined to the parameter k, while the running time of the reduction is polynomial in the input size n, where the order of the polynomial is independent of k.

Connected through hyperedge HE-1 (induced by source paper "backdoors to tractable valued csp"):
  with members:
    - "the complexity landscape of decompositional parameters for ilp"
    - "differential game logic"
    - "necessary conditions for tractability of valued csps"
    - "discovering archipelagos of tractability for constraint satisfaction and counting"
    - "on backdoors to tractable constraint languages"
    - "the complexity of conservative valued csps"
    - "backdoors to satisfaction"
    - "backdoors to tractable answer set programming"

Connected through hyperedge HE-2 (induced by source paper "strong backdoors for linear temporal logic"):
  with members:
    - "ltl fragments are hard for standard parameterisations"
    - "satisfiability of acyclic and almost acyclic cnf formulas"
    - "the complexity of clausal fragments of ltl"
    - "backdoors to satisfaction"
    - "backdoors to tractable answer set programming"
    - "the complexity of generalized satisfiability for linear temporal logic"
    - "clausal temporal resolution"

Connected through hyperedge HE-3 (induced by source paper "strong backdoors for default logic"):
  with members:
    - "satisfiability of acyclic and almost acyclic cnf formulas"
    - "backdoors to abduction"
    - "backdoors to satisfaction"
    - "backdoors to tractable answer set programming"
    - "the complexity of propositional implication"

Connected through hyperedge HE-4 (induced by source paper "dual normal logic programs the forgotten class"):
  with members:
    - "team building with answer set programming in the gioia tauro seaport"
    - "trichotomy and dichotomy results on the complexity of reasoning with disjunctive logic programs"
    - "characterising equilibrium logic and nested logic programs reductions and complexity1 2"
    - "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 "the parameterized complexity of reasoning problems beyond np"):
  with members:
    - "backdoors to abduction"
    - "on minimal constraint networks"
    - "unfolding partiality and disjunctions in stable model semantics"
    - "stable models and an alternative logic programming paradigm"

Connected through hyperedge HE-6 (induced by source paper "backdoors to abduction"):
  with members:
    - "backdoors to satisfaction"
    - "backdoors to acyclic sat"
    - "backdoors to tractable answer set programming"

Connected through hyperedge HE-7 (induced by source paper "backdoors to tractable answer set programming"):
  with members:
    - "guarantees and limits of preprocessing in constraint satisfaction and reasoning"
    - "the parameterized complexity of reasoning problems beyond np"
    - "numvc an efficient local search algorithm for minimum vertex cover"
    - "backdoors to abduction"
    - "the good the bad and the odd cycles in answer set programs"
    - "strong backdoors to bounded treewidth sat"
    - "strong backdoors to nested satisfiability"
    - "directed subset feedback vertex set is fixed parameter tractable"

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)