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 makespan approximation"
  Abstract: We study envy-free mechanisms for scheduling tasks on unrelated machines (agents) that approximately minimize the makespan. For indivisible tasks, we put forward an envy-free poly-time mechanism that approximates the minimal makespan to within a factor of $O(\log m)$, where $m$ is the number of machines. We also show a lower bound of $\Omega(\log m / \log\log m)$. This improves the recent result of Hartline {\sl et al.} \cite{Ahuva:2008} who give an upper bound of $(m+1)/2$, and a lower bound of $2-1/m$. For divisible tasks, we show that there always exists an envy-free poly-time mechanism with optimal makespan.

Connected through hyperedge HE-1 (induced by source paper "envy regret and social welfare loss"):
  with members:
    - "the ad types problem"
    - "online learning for measuring incentive compatibility in ad auctions"
    - "note on vcg vs price raising for matching markets"
    - "communication complexity of approximate nash equilibria"
    - "the price of anarchy in auctions"
    - "setting lower bounds on truthfulness"
    - "learning in auctions regret is hard envy is easy"
    - "adam a method for stochastic optimization"

Connected through hyperedge HE-2 (induced by source paper "combinatorial walrasian equilibrium"):
  with members:
    - "clearing markets via bundles"
    - "welfare and revenue guarantees for competitive bundling equilibrium"
    - "combinatorial auctions via posted prices"
    - "understanding incentives mechanism design becomes algorithm design"
    - "lower bound for envy free and truthful makespan approximation on related machines"
    - "optimization with demand oracles"
    - "an impossibility result for truthful combinatorial auctions with submodular valuations"
    - "bayesian incentive compatibility via fractional assignments"

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)