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: "designing exchange for online communities"
  Abstract: In many online systems, individuals provide services for each other. Typically, the recipient of the service obtains a benefit while the provider of the service incurs a cost. Assuming that benefit exceeds cost, provision of the service increases social welfare and should therefore be encouraged -- but the individuals providing the service gain no (immediate) benefit from providing the service and hence have an incentive to withhold service. This paper studies the design of a system to encourage provision of service; the emphasis is on how the system designer should choose a protocol -- a supply of tokens and suggested strategies -- to maximize social welfare. In choosing this protocol, the system designer must take into account that agents are self-interested, and hence will comply with the protocol if and only if it is in their interests to do so. Moreover, we insist that the chosen protocol must be consistent with (small) errors in the designer's knowledge of the system parameters (benefit, cost, discount factors of the agents). Thus, the chosen protocol must induce a robust equilibrium. The paper characterizes protocols that are consistent with robust equilibrium (for various ranges parameters of the population) and, among those, the protocols that maximize social welfare. The social welfare of the optimal equilibrium protocols approximates the first-best if agents are sufficiently patient.

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)