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: "agent based model for spot and balancing electricity markets"
  Abstract: We present a simple, yet realistic, agent-based model of an electricity market. The proposed model combines the spot and balancing markets with a resolution of one minute, which enables a more accurate depiction of the physical properties of the power grid. As a test, we compare the results obtained from our simulation to data from Nord Pool.

Connected through hyperedge HE-1 (induced by source paper "energy internet via packetized management enabling technologies and deployment challenges"):
  with members:
    - "event based electricity metering an autonomous method to determine transmission thresholds"
    - "finite blocklength communications in smart grids for dynamic spectrum access and locally licensed scenarios"
    - "sparse signal processing for grant free massive connectivity a future paradigm for random access protocols in the internet of things"
    - "why smart appliances may result in a stupid energy grid"
    - "increasing the throughput of an unlicensed wireless network through retransmissions"
    - "narrowband iot data transmission procedures for massive machine type communications"
    - "multi layer analysis of iot based systems"
    - "aggregation and resource scheduling in machine type communication networks a stochastic geometry approach"

Connected through hyperedge HE-2 (induced by source paper "why smart appliances may result in a stupid energy grid"):
  with members:
    - "dynamics of complex systems built as coupled physical communication and decision layers"
    - "models for the modern power grid"

Connected through hyperedge HE-3 (induced by source paper "implementing flexible demand real time price vs market integration"):
  with members:
    - "models for the modern power grid"
    - "volatility of power grids under real time pricing"

Connected through hyperedge HE-4 (induced by source paper "analysis of demand control policies using an agent based multi layer power system model"):
  with members:
    - "why smart appliances may result in a stupid energy grid"
    - "dynamics of complex systems built as coupled physical communication and decision layers"
    - "models for the modern power grid"
    - "a game theoretic approach to energy trading in the smart grid"

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.MA(Multiagent Systems)