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: "envy free pricing in multi unit markets"
  Abstract: We study the envy-free pricing problem in multi-unit markets with budgets, where there is a seller who brings multiple units of an item, while several buyers bring monetary endowments (budgets). Our goal is to compute an envy-free (item) price and allocation---i.e. an outcome where all the demands of the buyers are met given their budget constraints---which additionally achieves a desirable objective. We analyze markets with linear valuations, where the buyers are price takers and price makers, respectively. For the price taking scenario, we provide a polynomial time algorithm for computing the welfare maximizing envy-free pricing, followed by an FPTAS and exact algorithm---that is polynomial for a constant number of types of buyers---for computing a revenue maximizing envy-free pricing. #R##N#In the price taking model, where the buyers can strategize, we show a general impossibility of designing strategyproof and efficient mechanisms even with public budgets. On the positive side, we provide an optimal strategyproof mechanism for common budgets that simultaneously approximates the maximal revenue and welfare within a factor of 2 on all markets except monopsonies. #R##N#Finally, for markets with general valuations in the price taking scenario, we provide hardness results for computing envy-free pricing schemes that maximize revenue and welfare, as well as fully polynomial time approximation schemes for both problems.

Connected through hyperedge HE-1 (induced by source paper "on approximate welfare and revenue maximizing equilibria for size interchangeable bidders"):
  with members:
    - "envy free pricing in large markets approximating revenue and welfare"
    - "truth revelation in approximately efficient combinatorial auctions"

Connected through hyperedge HE-2 (induced by source paper "price doubling and item halving robust revenue guarantees for item pricing"):
  with members:
    - "a duality based unified approach to bayesian mechanism design"
    - "simple mechanisms for subadditive buyers via duality"
    - "mechanism design for subadditive agents via an ex ante relaxation"
    - "pricing to maximize revenue and welfare simultaneously in large markets"
    - "on the computational complexity of optimal simple mechanisms"
    - "on welfare approximation and stable pricing"
    - "secretary problems with non uniform arrival order"
    - "optimal auctions vs anonymous pricing"

Connected through hyperedge HE-3 (induced by source paper "revenue maximizing envy free pricing in matching markets with budgets"):
  with members:
    - "polyhedral clinching auctions and the adwords polytope"

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)