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: "facilitating adoption of network services with externalities via cost subsidization"
  Abstract: This paper investigates the adoption level of a network service where the net utility perceived by each user incorporates three key features, namely, user service affinity heterogeneity, a network externality, and a subscription cost. Services with network externality face a "chicken and egg" adoption problem in that the service requires customers in order to attract customers. In this paper we study cost subsidization as a means to "reach the knee" and thereby change the equilibrium adoption level from zero to one. By focusing on a simple subsidy structure and a simple model for user heterogeneity, we can derive explicit expressions for quantities of natural interest, such as the minimum subsidy required, the minimum subsidy duration, and the aggregate cost of the subsidy to the service provider. We show that small or large subsidies are inefficient, but that there is a Pareto efficient frontier for "intermediate" subsidies wherein subsidy duration and aggregate cost are in tension with one another.

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.SI(Social and Information Networks)