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: "improved approximations for free order prophets and second price auctions"
  Abstract: We study the fundamental problem of selling a single indivisible item to one of $n$ buyers with independent and potentially nonidentical value distributions. We focus on two simple and widely used selling mechanisms: the second price auction with \emph{eager} personalized reserve prices and the sequential posted price mechanism. Using a new approach, we improve the best-known performance guarantees for these mechanisms. We show that for every value of the number of buyers $n$, the eager second price (ESP) auction and sequential posted price mechanisms respectively earn at least $0.6620$ and $0.6543$ fractions of the optimal revenue. We also provide improved performance guarantees for these mechanisms when the number of buyers is small, which is the more relevant regime for many applications of interest. This in particular implies an improved bound of $0.6543$ for free-order prophet inequalities. #R##N#Motivated by our improved revenue bounds, we further study the problem of optimizing reserve prices in the ESP auctions when the sorted order of personalized reserve prices among bidders is exogenous. We show that this problem can be solved polynomially. In addition, by analyzing a real auction dataset from Google's advertising exchange, we demonstrate the effectiveness of order-based pricing.

Connected through hyperedge HE-1 (induced by source paper "assortment auctions a myersonian characterization for markov chain based choice models"):
  with members:
    - "prophet inequalities on the intersection of a matroid and a graph"
    - "multi stage and multi customer assortment optimization with inventory constraints"
    - "prophet secretary through blind strategies"
    - "a duality based unified approach to bayesian mechanism design"
    - "dynamic pricing under a static calendar"
    - "on policies for single leg revenue management with limited demand information"
    - "welfare maximization and truthfulness in mechanism design with ordinal preferences"
    - "mechanism design via correlation gap"

Connected through hyperedge HE-2 (induced by source paper "lp based approximation for personalized reserve prices"):
  with members:
    - "prophet secretary through blind strategies"
    - "prophet secretary surpassing the 1 1 e barrier"
    - "a field guide to personalized reserve prices"
    - "making the most of your samples"
    - "learning theory and algorithms for revenue optimization in second price auctions with reserve"
    - "mechanism design via correlation gap"
    - "optimal auctions with correlated bidders are easy"

Connected through hyperedge HE-3 (induced by source paper "how to hire secretaries with stochastic departures"):
  with members:
    - "online trading as a secretary problem"
    - "packing returning secretaries"
    - "prophet secretary surpassing the 1 1 e barrier"
    - "prophet secretary for combinatorial auctions and matroids"
    - "beyond matroids secretary problem and prophet inequality with general constraints"
    - "o log log rank competitive ratio for the matroid secretary problem"
    - "matroid prophet inequalities"

Connected through hyperedge HE-4 (induced by source paper "tight revenue gaps among simple mechanisms"):
  with members:
    - "prophet secretary through blind strategies"
    - "a duality based unified approach to bayesian mechanism design"
    - "nearly optimal pricing algorithms for production constrained and laminar bayesian selection"
    - "tight approximation ratio of anonymous pricing"
    - "approximate revenue maximization with multiple items"
    - "prophet secretary surpassing the 1 1 e barrier"
    - "prophet secretary for combinatorial auctions and matroids"
    - "simple mechanisms for subadditive buyers via duality"

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)