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: "spending is not easier than trading on the computational equivalence of fisher and arrow debreu equilibria"
  Abstract: It is a common belief that computing a market equilibrium in Fisher's spending model is easier than computing a market equilibrium in Arrow-Debreu's exchange model. This belief is built on the fact that we have more algorithmic success in Fisher equilibria than Arrow-Debreu equilibria. For example, a Fisher equilibrium in a Leontief market can be found in polynomial time, while it is PPAD-hard to compute an approximate Arrow-Debreu equilibrium in a Leontief market. #R##N#In this paper, we show that even when all the utilities are additively separable, piecewise-linear, and concave functions, finding an approximate equilibrium in Fisher's model is complete in PPAD. Our result solves a long-term open question on the complexity of market equilibria. To the best of our knowledge, this is the first PPAD-completeness result for Fisher's model.

Connected through hyperedge HE-1 (induced by source paper "dynamics of distributed updating in fisher markets"):
  with members:
    - "convex program duality fisher markets and nash social welfare"
    - "optimization learning and games with predictable sequences"
    - "tatonnement in ongoing markets of complementary goods"
    - "the complexity of non monotone markets"
    - "settling the complexity of arrow debreu equilibria in markets with additively separable utilities"
    - "settling the complexity of computing two player nash equilibria"

Connected through hyperedge HE-2 (induced by source paper "nash social welfare for indivisible items under separable piecewise linear concave utilities"):
  with members:
    - "characterization and computation of equilibria for indivisible goods"
    - "settling the complexity of arrow debreu equilibria in markets with additively separable utilities"

Connected through hyperedge HE-3 (induced by source paper "the complexity of fairness through equilibrium"):
  with members:
    - "inapproximability of nash equilibrium"
    - "the complexity of non monotone markets"
    - "a complexity view of markets with social influence"
    - "reducibility among fractional stability problems"
    - "settling the complexity of computing two player nash equilibria"
    - "on the approximation and smoothed complexity of leontief market equilibria"

Connected through hyperedge HE-4 (induced by source paper "on computability of equilibria in markets with production"):
  with members:
    - "the complexity of non monotone markets"
    - "a combinatorial polynomial algorithm for the linear arrow debreu market"
    - "concave generalized flows with applications to market equilibria"
    - "settling the complexity of arrow debreu equilibria in markets with additively separable utilities"

Connected through hyperedge HE-5 (induced by source paper "the complexity of non monotone markets"):
  with members:
    - "leontief exchange markets can solve multivariate polynomial equations yielding fixp and etr hardness"
    - "inapproximability of nash equilibrium"
    - "a complexity view of markets with social influence"
    - "settling the complexity of arrow debreu equilibria in markets with additively separable utilities"
    - "paths beyond local search a nearly tight bound for randomized fixed point computation"
    - "settling the complexity of computing two player nash equilibria"
    - "on the approximation and smoothed complexity of leontief market equilibria"

Connected through hyperedge HE-6 (induced by source paper "a survey of ppad completeness for computing nash equilibria"):
  with members:
    - "graphical models for game theory"
    - "a direct reduction from k player to 2 player approximate nash equilibrium"
    - "complexity results about nash equilibria"

Connected through hyperedge HE-7 (induced by source paper "non separable quasiconcave utilities are easy in a perfect price discrimination market model"):
  with members:
    - "rational convex programs their feasibility and the arrow debreu nash bargaining game"
    - "settling the complexity of arrow debreu equilibria in markets with additively separable utilities"

Connected through hyperedge HE-8 (induced by source paper "a complexity view of markets with social influence"):
  with members:
    - "settling the complexity of arrow debreu equilibria in markets with additively separable utilities"
    - "settling the complexity of computing two player nash equilibria"

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)