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: "ascending auctions and walrasian equilibrium"
  Abstract: We present a family of submodular valuation classes that generalizes gross substitute. We show that Walrasian equilibrium always exist for one class in this family, and there is a natural ascending auction which finds it. We prove some new structural properties on gross-substitute auctions which, in turn, show that the known ascending auctions for this class (Gul-Stacchetti and Ausbel) are, in fact, identical. We generalize these two auctions, and provide a simple proof that they terminate in a Walrasian equilibrium.

Connected through hyperedge HE-1 (induced by source paper "do prices coordinate markets"):
  with members:
    - "the sample complexity of revenue maximization"
    - "the optimal sample complexity of pac learning"
    - "ironing in the dark"
    - "learning economic parameters from revealed preferences"
    - "sampling and representation complexity of revenue maximization"
    - "optimal learners for multiclass problems"
    - "making the most of your samples"
    - "optimal provision after wait in healthcare"

Connected through hyperedge HE-2 (induced by source paper "double auctions in markets for multiple kinds of goods"):
  with members:
    - "approximating gains from trade in two sided markets via simple mechanisms"
    - "polyhedral clinching auctions for two sided markets"
    - "fixed price approximability of the optimal gain from trade"
    - "approximately efficient two sided combinatorial auctions"
    - "the pseudo dimension of near optimal auctions"
    - "on random sampling auctions for digital goods"
    - "prior independent mechanisms for scheduling"
    - "envy freedom and prior free mechanism design"

Connected through hyperedge HE-3 (induced by source paper "ad exchange envy free auctions with mediators"):
  with members:
    - "online ad assignment with an ad exchange"
    - "doubleclick ad exchange auction"
    - "combinatorial auctions with decreasing marginal utilities"

Connected through hyperedge HE-4 (induced by source paper "walrasian s characterization and a universal ascending auction"):
  with members:
    - "combinatorial auctions with decreasing marginal utilities"

Connected through hyperedge HE-5 (induced by source paper "budgetary effects on pricing equilibrium in online markets"):
  with members:
    - "convergence of tâtonnement in fisher markets"
    - "price competition in online combinatorial markets"
    - "the pricing war continues on competitive multi item pricing"
    - "on the efficiency of the walrasian mechanism"
    - "combinatorial auctions with decreasing marginal utilities"

Connected through hyperedge HE-6 (induced by source paper "computing walrasian equilibria fast algorithms and structural properties"):
  with members:
    - "do prices coordinate markets"
    - "the invisible hand of dynamic market pricing"
    - "a faster cutting plane method and its implications for combinatorial and convex optimization"

Connected through hyperedge HE-7 (induced by source paper "analysis of digital knapsack based sealed bid auction"):
  with members:
    - "the piggy bank cryptographic trope"
    - "generalized public key transformations with side information"
    - "a novel approach to fully private and secure auction a sealed bid knapsack auction"
    - "selling privacy at auction"

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)