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: "joint energy and spectrum cooperation for cellular communication systems"
  Abstract: Powered by renewable energy sources, cellular com- munication systems usually have different wireless traffic loads and available resources over time. To match their traffics, it is beneficial for two neighboring systems to cooperate in resource sharing when one is excessive in one resource (e.g., spectrum), while the other is sufficient in another (e.g., energy). In this paper, we propose a joint energy and spectrum cooperation scheme be- tween different cellular systems to reduce their operational costs. When the two systems are fully cooperative in nature (e.g., belong- ing to the same entity), we formulate the cooperation problem as a convex optimization problem to minimize their weighted sum cost and obtain the optimal solution in closed form. We also study another partially cooperative scenario where the two systems have their own interests. We show that the two systems seek for partial cooperation as long as they find inter-system complementarity between the energy and spectrum resources. Under the partial cooperation conditions, we propose a distributed algorithm for the two systems to gradually and simultaneously reduce their costs from the non-cooperative benchmark to the Pareto optimum. This distributed algorithm also has proportional fair cost reduction by reducing each system's cost proportionally over iterations. Finally, we provide numerical results to validate the convergence of the distributed algorithm to the Pareto optimality and compare the centralized and distributed cost reduction approaches for fully and partially cooperative scenarios.

Connected through hyperedge HE-1 (induced by source paper "a new relation between energy efficiency and spectral efficiency in wireless communications systems"):
  with members:
    - "energy efficient scheduling and power allocation in downlink ofdma networks with base station coordination"
    - "cost aware green cellular networks with energy and communication cooperation"
    - "framework for link level energy efficiency optimization with informed transmitter"

Connected through hyperedge HE-2 (induced by source paper "distributed resource allocation for network slicing over licensed and unlicensed bands"):
  with members:
    - "network slicing games enabling customization in multi tenant networks"
    - "coordination protocol for inter operator spectrum sharing in co primary 5g small cell networks"
    - "sharing of unlicensed spectrum by strategic operators"
    - "investment and pricing with spectrum uncertainty a cognitive operator s perspective"
    - "cooperative games with overlapping coalitions"

Connected through hyperedge HE-3 (induced by source paper "joint energy bandwidth allocation for multi user channels with cooperating hybrid energy nodes"):
  with members:
    - "iterative dynamic water filling for fading multiple access channels with energy harvesting"
    - "comp meets smart grid a new communication and energy cooperation paradigm"
    - "energy cooperation in energy harvesting communications"
    - "throughput maximization for the gaussian relay channel with energy harvesting constraints"
    - "energy cooperation in cellular networks with renewable powered base stations"
    - "optimal power allocation for energy harvesting and power grid coexisting wireless communication systems"
    - "relaying protocols for wireless energy harvesting and information processing"
    - "decentralized delay optimal control for interference networks with limited renewable energy storage"

Connected through hyperedge HE-4 (induced by source paper "optimal energy and data routing in networks with energy cooperation"):
  with members:
    - "cost aware green cellular networks with energy and communication cooperation"
    - "application of smart antenna technologies in simultaneous wireless information and power transfer"
    - "energy cooperation in energy harvesting communications"
    - "energy cooperation in cellular networks with renewable powered base stations"
    - "wireless information and power transfer architecture design and rate energy tradeoff"
    - "enabling wireless power transfer in cellular networks architecture modeling and deployment"
    - "optimal energy allocation for wireless communications with energy harvesting constraints"
    - "transmission with energy harvesting nodes in fading wireless channels optimal policies"

Connected through hyperedge HE-5 (induced by source paper "energy group buying with loading sharing for green cellular networks"):
  with members:
    - "green 5g heterogeneous networks through dynamic small cell operation"
    - "comp meets smart grid a new communication and energy cooperation paradigm"
    - "bargaining based mobile data offloading"
    - "what will 5g be"
    - "cost aware green cellular networks with energy and communication cooperation"
    - "cooperative energy trading in comp systems powered by smart grids"
    - "energy cooperation in cellular networks with renewable powered base stations"
    - "green cellular networks a survey some research issues and challenges"

Connected through hyperedge HE-6 (induced by source paper "green 5g heterogeneous networks through dynamic small cell operation"):
  with members:
    - "energy group buying with loading sharing for green cellular networks"
    - "dynamic base station operation in large scale green cellular networks"
    - "spatial throughput maximization of wireless powered communication networks"
    - "what will 5g be"
    - "offloading in heterogeneous networks modeling analysis and design insights"
    - "user association for load balancing in heterogeneous cellular networks"
    - "optimal power and range adaptation for green broadcasting"
    - "green cellular networks a survey some research issues and challenges"

Connected through hyperedge HE-7 (induced by source paper "energy efficient small cell with spectrum power trading"):
  with members:
    - "fundamental green tradeoffs progresses challenges and impacts on 5g networks"
    - "an overview of sustainable green 5g networks"
    - "energy efficient resource allocation for wireless powered communication networks"
    - "a traffic load balancing framework for software defined radio access networks powered by hybrid energy sources"
    - "quantifying potential energy efficiency gain in green cellular wireless networks"
    - "energy efficiency optimization for mimo ofdm mobile multimedia communication systems with qos constraints"
    - "energy efficient resource allocation in ofdma systems with hybrid energy harvesting base station"
    - "achieving maximum energy efficiency in multi relay ofdma cellular networks a fractional programming approach"

Connected through hyperedge HE-8 (induced by source paper "spectrum power trading for energy efficient small cell"):
  with members:
    - "fundamental green tradeoffs progresses challenges and impacts on 5g networks"
    - "energy efficient small cell with spectrum power trading"
    - "energy efficient resource allocation for wireless powered communication networks"

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.IT(Information Theory)