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: "a simple proof of fast polarization"
  Abstract: Fast polarization is an important and useful property of polar codes. It was proved for the binary polarizing $2 \times 2$ kernel by Arikan and Telatar. The proof was later generalized by Sasoglu. We give a simplified proof.

Connected through hyperedge HE-1 (induced by source paper "polar codes for the deletion channel weak and strong polarization"):
  with members:
    - "universal polarization for processes with memory"
    - "capacity upper bounds for deletion type channels"
    - "fast polarization for processes with memory"
    - "polar coding for the binary erasure channel with deletions"
    - "polar coding for processes with memory"
    - "joint successive cancellation decoding of polar codes over intersymbol interference channels"
    - "list decoding of polar codes"
    - "polar codes characterization of exponent bounds and constructions"

Connected through hyperedge HE-2 (induced by source paper "universal polarization for processes with memory"):
  with members:
    - "fast polarization for processes with memory"
    - "polar coding for processes with memory"
    - "construction of polar codes for arbitrary discrete memoryless channels"
    - "on the construction of polar codes for channels with moderate input alphabet sizes"
    - "universal polar codes for more capable and less noisy channels and sources"
    - "joint successive cancellation decoding of polar codes over intersymbol interference channels"
    - "universal source polarization and an application to a multi user problem"
    - "channel upgradation for non binary input alphabets and macs"

Connected through hyperedge HE-3 (induced by source paper "fast polarization for processes with memory"):
  with members:
    - "polar codes with a stepped boundary"
    - "polar coding for processes with memory"
    - "joint successive cancellation decoding of polar codes over intersymbol interference channels"
    - "achieving the secrecy capacity of wiretap channels using polar codes"
    - "polar codes are optimal for lossy source coding"
    - "polarization for arbitrary discrete memoryless channels"
    - "on the rate of channel polarization"

Connected through hyperedge HE-4 (induced by source paper "channel capacity of polar coding with a given polar mismatched successive cancellation decoder"):
  with members:
    - "on the scaling exponent of polar codes for binary input energy harvesting channels"
    - "a split reduced successive cancellation list decoder for polar codes"
    - "a low latency list successive cancellation decoding implementation for polar codes"
    - "a high throughput list decoder architecture for polar codes"
    - "fast list decoders for polar codes"
    - "symbol decision successive cancellation list decoder for polar codes"
    - "polar coding for processes with memory"
    - "erasure schemes using generalized polar codes zero undetected error capacity and performance trade offs"

Connected through hyperedge HE-5 (induced by source paper "polar coding for processes with memory"):
  with members:
    - "fast polarization for processes with memory"
    - "channel polarization a method for constructing capacity achieving codes for symmetric binary input memoryless channels"
    - "on the rate of channel polarization"

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)