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: "spider solitaire is np complete"
  Abstract: This project investigates the potential of computers to solve complex tasks such as games. The paper proves that the complexity of a generalized version of spider solitaire is NP-Complete and uses much of structure of the proof that FreeCell is NP-Hard in the paper Helmert, M. "Complexity Results for Standard Benchmark Domains in Planning." Artificial Intelligence 143.2 (2003): 219-62. Print. A given decision problem falls in to the class NP-Complete if it is proven to be both in NP and in NP-Hard. To prove that this is the case the paper shows that, not only do the kinds of possible moves that can be reversed prove this, but it is also shown that no spider solitaire game of size n will take more than a polynomial number of moves to complete if such a completion is possible. The paper reduces 3-SAT to SpiderSolitaire (the name used throughout the proof when referring to the generalized version of popular solitaire variant "Spider Solitaire") by showing that any 3-SAT instance can be replicated using an appropriately arranged initial tableau. The example provided reinforces the proof of NP-Hardness and helps to make the proof easier to understand, but the definitive proof lies in the equations providing instruction on how to set up any 3-SAT instance of clause size C as a instance of SpiderSolitaire.

Connected through hyperedge HE-1 (induced by source paper "computational complexity of games and puzzles"):
  with members:
    - "the computational complexity of portal and other 3d video games"
    - "combinatorial game complexity an introduction with poset games"
    - "classic nintendo games are computationally hard"
    - "lemmings is pspace complete"
    - "gaming is a hard job but someone has to do it"
    - "tetris is hard even to approximate"

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.CC(Computational Complexity)