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: "introducing hierarchy in energy games"
  Abstract: In this work, we introduce hierarchy in wireless networks that can be modeled by a decentralized multiple access channel and for which energy-efficiency is the main performance index. In these networks users are free to choose their power control strategy to selfishly maximize their energy-efficiency. Specifically, we introduce hierarchy in two different ways: 1. Assuming single-user decoding at the receiver, we investigate a Stackelberg formulation of the game where one user is the leader whereas the other users are assumed to be able to react to the leader's decisions; 2. Assuming neither leader nor followers among the users, we introduce hierarchy by assuming successive interference cancellation at the receiver. It is shown that introducing a certain degree of hierarchy in non-cooperative power control games not only improves the individual energy efficiency of all the users but can also be a way of insuring the existence of a non-saturated equilibrium and reaching a desired trade-off between the global network performance at the equilibrium and the requested amount of signaling. In this respect, the way of measuring the global performance of an energy-efficient network is shown to be a critical issue.

Connected through hyperedge HE-1 (induced by source paper "distributed power control with partial channel state information performance characterization and design"):
  with members:
    - "interference coordination via power domain channel estimation"
    - "ultra dense small cell networks turning density into energy efficiency"
    - "a survey of energy efficient techniques for 5g networks and challenges ahead"
    - "coordination in distributed networks via coded actions with application to power control"
    - "coded power control performance analysis"
    - "robust precoding for network mimo with hierarchical csit"
    - "a game theoretic analysis for energy efficient heterogeneous networks"
    - "mac with action dependent state information at one encoder"

Connected through hyperedge HE-2 (induced by source paper "on the two user multi carrier joint channel selection and power control game"):
  with members:
    - "toward fully coordinated multi level multi carrier energy efficient networks"
    - "spectrum coordination in energy efficient cognitive radio networks"
    - "on the energy spectral efficiency trade off of the mrc receiver in massive mimo systems with transceiver power consumption"
    - "spectral efficiency and energy efficiency of ofdm systems impact of power amplifiers and countermeasures"
    - "quantifying potential energy efficiency gain in green cellular wireless networks"
    - "a game theoretic analysis for energy efficient heterogeneous networks"
    - "energy efficient precoding for multiple antenna terminals"
    - "femtocell networks a survey"

Connected through hyperedge HE-3 (induced by source paper "a cross layer approach for distributed energy efficient power control in interference networks"):
  with members:
    - "green power control in cognitive wireless networks"
    - "implicit cooperation in distributed energy efficient networks"
    - "cross layer design for green power control"
    - "energy efficient precoding for multiple antenna terminals"
    - "asynchronous capacity per unit cost"
    - "on the base station selection and base station sharing in self configuring networks"
    - "competitive design of multiuser mimo systems based on game theory a unified view"
    - "energy efficient communications in cdma networks a game theoretic analysis considering operating costs"

Connected through hyperedge HE-4 (induced by source paper "cross layer distributed power control a repeated game formulation to improve the sum energy efficiency"):
  with members:
    - "a cross layer approach for distributed energy efficient power control in interference networks"
    - "cross layer design for green power control"
    - "framework for link level energy efficiency optimization with informed transmitter"
    - "energy efficient precoding for multiple antenna terminals"
    - "methodologies for analyzing equilibria in wireless games"
    - "energy efficient communications in cdma networks a game theoretic analysis considering operating costs"

Connected through hyperedge HE-5 (induced by source paper "pricing based distributed energy efficient beamforming for miso interference channels"):
  with members:
    - "energy efficient power control a look at 5g wireless technologies"
    - "what will 5g be"
    - "framework for link level energy efficiency optimization with informed transmitter"
    - "optimal linear precoding strategies for wideband noncooperative systems based on game theory part i nash equilibria"
    - "a distributed merge and split algorithm for fair cooperation in wireless networks"

Connected through hyperedge HE-6 (induced by source paper "spectrum coordination in energy efficient cognitive radio networks"):
  with members:
    - "a game theoretic analysis for energy efficient heterogeneous networks"
    - "distributed learning policies for power allocation in multiple access channels"
    - "femtocell networks a survey"
    - "energy efficient resource allocation in wireless networks"
    - "spectral efficiency of spectrum pooling systems"

Connected through hyperedge HE-7 (induced by source paper "distributed energy efficient channel allocation"):
  with members:
    - "asymptotically optimal resource block allocation with limited feedback"
    - "distributed learning for channel allocation over a shared spectrum"
    - "game theoretic dynamic channel allocation for frequency selective interference channels"
    - "a survey of energy efficient techniques for 5g networks and challenges ahead"
    - "distributed channel assignment in cognitive radio networks stable matching and walrasian equilibrium"
    - "matching theory for future wireless networks fundamentals and applications"
    - "fully distributed optimal channel assignment for open spectrum access"
    - "on optimizing energy efficiency in multi radio multi channel wireless networks"

Connected through hyperedge HE-8 (induced by source paper "energy efficient scheduling and power allocation in downlink ofdma networks with base station coordination"):
  with members:
    - "what will 5g be"
    - "fundamental limits of cooperation"
    - "framework for link level energy efficiency optimization with informed transmitter"
    - "energy efficient precoding for multiple antenna terminals"
    - "slow adaptive ofdma systems through chance constrained programming"
    - "energy efficient communications in cdma networks a game theoretic analysis considering operating costs"

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)