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: "adding negative prices to priced timed games"
  Abstract: Priced timed games (PTGs) are two-player zero-sum games played on the infinite graph of configurations of priced timed automata where two players take turns to choose transitions in order to optimize cost to reach target states. Bouyer et al. and Alur, Bernadsky, and Madhusudan independently proposed algorithms to solve PTGs with nonnegative prices under certain divergence restriction over prices. Brihaye, Bruyere, and Raskin later provided a justification for such a restriction by showing the undecidability of the optimal strategy synthesis problem in the absence of this divergence restriction. This problem for PTGs with one clock has long been conjectured to be in polynomial time, however the current best known algorithm, by Hansen, Ibsen-Jensen, and Miltersen, is exponential. We extend this picture by studying PTGs with both negative and positive prices. We refine the undecidability results for optimal strategy synthesis problem, and show undecidability for several variants of optimal reachability cost objectives including reachability cost, time-bounded reachability cost, and repeated reachability cost objectives. We also identify a subclass with bi-valued price-rates and give a pseudo-polynomial (polynomial when prices are nonnegative) algorithm to partially answer the conjecture on the complexity of one-clock PTGs.

Connected through hyperedge HE-1 (induced by source paper "one clock priced timed games are pspace hard"):
  with members:
    - "simple priced timed games are not that simple"
    - "a faster algorithm for solving one clock priced timed games"
    - "two player reachability price games on single clock timed automata"
    - "reachability time games on timed automata"

Connected through hyperedge HE-2 (induced by source paper "timed network games with clocks"):
  with members:
    - "mean payoff games on timed automata"
    - "reachability in two clock timed automata is pspace complete"
    - "on subgame perfection in quantitative reachability games"
    - "timed parity games complexity and robustness"

Connected through hyperedge HE-3 (induced by source paper "optimal reachability in divergent weighted timed games"):
  with members:
    - "simple priced timed games are not that simple"
    - "to reach or not to reach efficient algorithms for total payoff games"
    - "a faster algorithm for solving one clock priced timed games"
    - "two player reachability price games on single clock timed automata"
    - "reachability time games on timed automata"

Connected through hyperedge HE-4 (induced by source paper "expected reachability time games"):
  with members:
    - "optimizing performance of continuous time stochastic systems using timeout synthesis"
    - "quantitative games on probabilistic timed automata"
    - "adaptive scheduling of data paths using uppaal tiga"
    - "reachability time games on timed automata"
    - "model checking probabilistic timed automata with one or two clocks"

Connected through hyperedge HE-5 (induced by source paper "simple priced timed games are not that simple"):
  with members:
    - "to reach or not to reach efficient algorithms for total payoff games"
    - "a faster algorithm for solving one clock priced timed games"
    - "two player reachability price games on single clock timed automata"

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)