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 practical use of variable elimination in constraint optimization problems still life as a case study"
  Abstract: Variable elimination is a general technique for constraint processing. It is often discarded because of its high space complexity. However, it can be extremely useful when combined with other techniques. In this paper we study the applicability of variable elimination to the challenging problem of finding still-lifes. We illustrate several alternatives: variable elimination as a stand-alone algorithm, interleaved with search, and as a source of good quality lower bounds. We show that these techniques are the best known option both theoretically and empirically. In our experiments we have been able to solve the n = 20 instance, which is far beyond reach with alternative approaches.

Connected through hyperedge HE-1 (induced by source paper "a logic algebraic tool for reasoning with knowledge based systems"):
  with members:
    - "variable forgetting in reasoning about knowledge"
    - "propositional independence formula variable independence and forgetting"

Connected through hyperedge HE-2 (induced by source paper "when you must forget beyond strong persistence when forgetting in answer set programming"):
  with members:
    - "the rise and fall of semantic rule updates based on se models"
    - "the logical difference for the lightweight description logic el"
    - "a system of interaction and structure"
    - "semantical characterizations and complexity of equivalences in answer set programming"
    - "an abductive framework for computing knowledge base updates"
    - "propositional independence formula variable independence and forgetting"

Connected through hyperedge HE-3 (induced by source paper "solving weighted constraint satisfaction problems with memetic exact hybrid algorithms"):
  with members:
    - "finding still lifes with memetic exact hybrid algorithms"

Connected through hyperedge HE-4 (induced by source paper "a logical approach to efficient max sat solving"):
  with members:
    - "new inference rules for max sat"
    - "arc consistency for soft constraints"

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.AI(Artificial Intelligence)