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: "convergence analysis of saddle point problems in time varying wireless systems control theoretical approach"
  Abstract: Saddle point problems arise from many wireless applications, and primal-dual iterative algorithms are widely applied to find the saddle points. In the existing literature, the convergence results of such algorithms are established assuming the problem specific parameters remain unchanged during the iterations. However, this assumption is unrealistic in time varying wireless systems, as explicit message passing is usually involved in the iterations and the channel state information (CSI) may change in a time scale comparable to the algorithm update period. This paper investigates the convergence behavior and the tracking error of primal-dual iterative algorithms under time varying CSI. The convergence results are established by studying the stability of an equivalent virtual dynamic system derived in the paper, and the Lyapunov theory is applied for the stability analysis. We show that the average tracking error is proportional to the time variation rate of the CSI. Based on these analyses, we also derive an adaptive primal-dual algorithm by introducing a compensation term to reduce the tracking error under the time varying CSI.

Connected through hyperedge HE-1 (induced by source paper "exponential stability of primal dual gradient dynamics with non strong convexity"):
  with members:
    - "stochastic variance reduction methods for policy evaluation"
    - "stochastic variance reduction methods for saddle point problems"
    - "design and stability of load side primary frequency control in power systems"

Connected through hyperedge HE-2 (induced by source paper "cluster based distributed augmented lagrangian algorithm for a class of constrained convex optimization problems"):
  with members:
    - "linear convergence rate of a class of distributed augmented lagrangian algorithms"
    - "zero gradient sum algorithms for distributed convex optimization the continuous time case"

Connected through hyperedge HE-3 (induced by source paper "two tier precoding for fdd multi cell massive mimo time varying interference networks"):
  with members:
    - "convergence analysis of mixed timescale cross layer stochastic optimization"
    - "joint spatial division and multiplexing opportunistic beamforming and user grouping"
    - "approaching the capacity of wireless networks through distributed interference alignment"

Connected through hyperedge HE-4 (induced by source paper "convergence analysis of mixed timescale cross layer stochastic optimization"):
  with members:
    - "delay analysis of max weight queue algorithm for time varying wireless ad hoc networks control theoretical approach"

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)