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: "sbba a strongly budget balanced double auction mechanism"
  Abstract: In a seminal paper, McAfee (1992) presented the first dominant strategy truthful mechanism for double auction. His mechanism attains nearly optimal gain-from-trade when the market is sufficiently large. However, his mechanism may leave money on the table, since the price paid by the buyers may be higher than the price paid to the sellers. This money is included in the gain-from-trade and in some cases it accounts for almost all the gain-from-trade, leaving almost no gain-from-trade to the traders. We present SBBA: a variant of McAfee’s mechanism which is strongly budget-balanced. There is a single price, all money is exchanged between buyers and sellers and no money is left on the table. This means that all gain-from-trade is enjoyed by the traders. We generalize this variant to spatially-distributed markets with transit costs.

Connected through hyperedge HE-1 (induced by source paper "efficient two sided markets with limited information"):
  with members:
    - "optimal single choice prophet inequalities from samples"
    - "bulow klemperer style results for welfare maximization in two sided markets"
    - "improved truthful mechanisms for combinatorial auctions with submodular bidders"
    - "online trading as a secretary problem"
    - "the best of both worlds asymptotically efficient mechanisms with a guarantee on the expected gains from trade"
    - "approximating gains from trade in two sided markets via simple mechanisms"
    - "fixed price approximability of the optimal gain from trade"
    - "online market intermediation"

Connected through hyperedge HE-2 (induced by source paper "online trading as a secretary problem"):
  with members:
    - "approximating gains from trade in two sided markets via simple mechanisms"
    - "fixed price approximability of the optimal gain from trade"
    - "online market intermediation"
    - "combinatorial auctions via posted prices"
    - "algorithms for secretary problems on graphs and hypergraphs"

Connected through hyperedge HE-3 (induced by source paper "fixed price approximability of the optimal gain from trade"):
  with members:
    - "approximating gains from trade in two sided markets via simple mechanisms"
    - "online market intermediation"
    - "markets with strategic multi minded mediators"
    - "approximately efficient two sided combinatorial auctions"
    - "online truthful mechanisms for multi sided markets"

Connected through hyperedge HE-4 (induced by source paper "muda a truthful multi unit double auction mechanism"):
  with members:
    - "approximating gains from trade in two sided markets via simple mechanisms"
    - "polyhedral clinching auctions for two sided markets"
    - "markets with strategic multi minded mediators"
    - "approximately efficient two sided combinatorial auctions"
    - "envy freedom and prior free mechanism design"

Connected through hyperedge HE-5 (induced by source paper "approximately efficient two sided combinatorial auctions"):
  with members:
    - "the best of both worlds asymptotically efficient mechanisms with a guarantee on the expected gains from trade"
    - "approximating gains from trade in two sided markets via simple mechanisms"
    - "fixed price approximability of the optimal gain from trade"
    - "almost efficient mechanisms for bilateral trading"
    - "combinatorial auctions via posted prices"
    - "polymatroid prophet inequalities"
    - "matroid prophet inequalities"

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)