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: "structured ldpc codes from permutation matrices free of small trapping sets"
  Abstract: This paper introduces a class of structured lowdensity parity-check (LDPC) codes whose parity check matrices are arrays of permutation matrices. The permutation matrices are obtained from Latin squares and form a finite field under some matrix operations. They are chosen so that the Tanner graphs do not contain subgraphs harmful to iterative decoding algorithms. The construction of column-weight-three codes is presented. Although the codes are optimized for the Gallager A/B algorithm over the binary symmetric channel (BSC), their error performance is very good on the additive white Gaussian noise channel (AWGNC) as well.

Connected through hyperedge HE-1 (induced by source paper "the cycle consistency matrix approach to absorbing sets in separable circulant based ldpc codes"):
  with members:
    - "design of finite length irregular protograph codes with low error floors over the binary input awgn channel using cyclic liftings"
    - "absorbing set spectrum approach for practical code design"
    - "cyclic and quasi cyclic ldpc codes on row and column constrained parity check matrices and their trapping sets"
    - "lowering the error floor of ldpc codes using cyclic liftings"
    - "shortened array codes of large girth"

Connected through hyperedge HE-2 (induced by source paper "ldpc decoding with limited precision soft information in flash memories"):
  with members:
    - "the cycle consistency matrix approach to absorbing sets in separable circulant based ldpc codes"

Connected through hyperedge HE-3 (induced by source paper "absorbing set spectrum approach for practical code design"):
  with members:
    - "on the dynamics of the error floor behavior in regular ldpc codes"
    - "shortened array codes of large girth"

Connected through hyperedge HE-4 (induced by source paper "cyclic and quasi cyclic ldpc codes on row and column constrained parity check matrices and their trapping sets"):
  with members:
    - "on trapping sets and guaranteed error correction capability of ldpc codes and gldpc codes"
    - "on the hardness of approximating stopping and trapping sets in ldpc codes"
    - "instanton analysis of low density parity check codes in the error floor regime"
    - "a general method for finding low error rates of ldpc codes"

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)