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: "market implementation of multiple arrival multiple deadline differentiated energy services"
  Abstract: An increasing concern in power systems is on how to elicit flexibilities in demands for better supply/demand balance. To this end, several differentiated energy services have been put forward, wherein demands are discriminated by their different flexibility levels. Motivated by the duration-differentiated energy services, we have proposed energy services differentiated by durations, arrival times, and deadlines. The purpose of this paper is to study the market implementation of such multiple-arrival multiple-deadline differentiated energy services. To verify the economic feasibility, we establish that in a forward market, there exists an efficient competitive equilibrium which attains the maximum social welfare. In addition, we show that future information will influence current decisions on power delivery by studying a special kind of causal allocation policy. Finally, we propose two tractable integer programs, namely the optimal arbitrage and the minimum-cost allocation problems, which can be embedded in a two-level hierarchical real-time implementation of differentiated energy services.

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.SY(Systems and Control)