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: "lemmings is pspace complete"
  Abstract: Lemmings is a computer puzzle game developed by DMA Design and published by Psygnosis in 1991, in which the player has to guide a tribe of lemming creatures to safety through a hazardous landscape, by assigning them specific skills that modify their behavior in different ways. In this paper we study the optimization problem of saving the highest number of lemmings in a given landscape with a given number of available skills. #R##N#We prove that the game is PSPACE-complete, even if there is only one lemming to save, and only Builder and Basher skills are available. We thereby settle an open problem posed by Cormode in 2004, and again by Forisek in 2010. However we also prove that, if we restrict the game to levels in which the available Builder skills are only polynomially many (and there is any number of other skills), then the game is solvable in NP. Similarly, if the available Basher, Miner, and Digger skills are polynomially many, the game is solvable in NP. #R##N#Furthermore, we show that saving the maximum number of lemmings is APX-hard, even when only one type of skill is available, whatever this skill is. This contrasts with the membership in P of the decision problem restricted to levels with no "deadly areas" (such as water or traps) and only Climber and Floater skills, as previously established by Cormode.

Connected through hyperedge HE-1 (induced by source paper "the computational complexity of angry birds"):
  with members:
    - "the computational complexity of portal and other 3d video games"
    - "pspace completeness of bloxorz and of games with 2 buttons"
    - "braid is undecidable"
    - "a bayesian ensemble regression framework on the angry birds game"
    - "bejeweled candy crush and other match three games are np hard"
    - "towards a theory of mind inspired generic decision making framework"
    - "candy crush is np hard"
    - "classic nintendo games are computationally hard"

Connected through hyperedge HE-2 (induced by source paper "the computational complexity of fire emblem series and similar tactical role playing games"):
  with members:
    - "computational complexity of games and puzzles"
    - "trainyard is np hard"
    - "on planar variants of the monotone satisfiability problem with bounded variable appearances"
    - "the computational complexity of portal and other 3d video games"
    - "candy crush is np hard"
    - "classic nintendo games are computationally hard"
    - "the complexity of the puzzles of final fantasy xiii 2"
    - "gaming is a hard job but someone has to do it"

Connected through hyperedge HE-3 (induced by source paper "a note on hardness frameworks and computational complexity of xiangqi and janggi"):
  with members:
    - "classic nintendo games are computationally hard"
    - "gaming is a hard job but someone has to do it"
    - "playing games with algorithms algorithmic combinatorial game theory"

Connected through hyperedge HE-4 (induced by source paper "a general theory of motion planning complexity characterizing which gadgets make games hard"):
  with members:
    - "computational complexity of motion planning of a robot through simple gadgets"
    - "push pull block puzzles are hard"
    - "pspace completeness of bloxorz and of games with 2 buttons"
    - "classic nintendo games are computationally hard"
    - "gaming is a hard job but someone has to do it"
    - "playing games with algorithms algorithmic combinatorial game theory"

Connected through hyperedge HE-5 (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"
    - "gaming is a hard job but someone has to do it"
    - "spider solitaire is np complete"
    - "tetris is hard even to approximate"

Connected through hyperedge HE-6 (induced by source paper "the computational complexity of portal and other 3d video games"):
  with members:
    - "candy crush is np hard"
    - "the complexity of the puzzles of final fantasy xiii 2"
    - "playing games with algorithms algorithmic combinatorial game theory"

Connected through hyperedge HE-7 (induced by source paper "braid is undecidable"):
  with members:
    - "gaming is a hard job but someone has to do it"

Connected through hyperedge HE-8 (induced by source paper "classic nintendo games are computationally hard"):
  with members:
    - "gaming is a hard job but someone has to do it"
    - "pushpush and push 1 are np hard in 2d"

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.GT(Computer Science and Game Theory)