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: "upgraded approximation of non binary alphabets for polar code construction"
  Abstract: An algorithm is presented for approximating a single-user channel with a prime input alphabet size. The result is an upgraded version of the channel with a reduced output alphabet size. It is shown that this algorithm can be used to reduce the output alphabet size to the input alphabet size in most cases.

Connected through hyperedge HE-1 (induced by source paper "construction of polar codes for arbitrary discrete memoryless channels"):
  with members:
    - "a comparative study of polar code constructions for the awgn channel"
    - "on the construction of polar codes for channels with moderate input alphabet sizes"
    - "ergodic theory meets polarization ii a foundation of polarization theory"
    - "practical polar code construction using generalised generator matrices"
    - "channel upgradation for non binary input alphabets and macs"
    - "on the construction and decoding of concatenated polar codes"
    - "universal polar codes"
    - "constructing polar codes using iterative bit channel upgrading"

Connected through hyperedge HE-2 (induced by source paper "on the construction of polar codes for channels with moderate input alphabet sizes"):
  with members:
    - "construction of polar codes for arbitrary discrete memoryless channels"
    - "an entropy sumset inequality and polynomially fast convergence to shannon capacity over all alphabets"
    - "channel upgradation for non binary input alphabets and macs"
    - "on the construction of polar codes"
    - "source and channel polarization over finite fields and reed solomon matrices"
    - "how to construct polar codes"
    - "polar codes with mixed kernels"
    - "quantization of binary input discrete memoryless channels"

Connected through hyperedge HE-3 (induced by source paper "channel upgradation for non binary input alphabets and macs"):
  with members:
    - "construction of polar codes for arbitrary discrete memoryless channels"
    - "on the construction of polar codes for channels with moderate input alphabet sizes"
    - "how to achieve the capacity of asymmetric channels"
    - "polar codes for the two user multiple access channel"
    - "on the construction of polar codes"
    - "how to construct polar codes"
    - "achieving the secrecy capacity of wiretap channels using polar codes"
    - "polar coding for secure transmission and key agreement"

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)