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: "the perfect binary one error correcting codes of length 15 part ii properties"
  Abstract: A complete classification of the perfect binary one-error-correcting codes of length 15, as well as their extensions of length 16, was recently carried out in [P. R. J. O?stergard and O. Pottonen, ?The perfect binary one-error-correcting codes of length 15: Part I-Classification,? IEEE Trans. Inf. Theory vol. 55, pp. 4657-4660, 2009]. In the current accompanying work, the classified codes are studied in great detail, and their main properties are tabulated. The results include the fact that 33 of the 80 Steiner triple systems of order 15 occur in such codes. Further understanding is gained on full-rank codes via switching, as it turns out that all but two full-rank codes can be obtained through a series of such transformations from the Hamming code. Other topics studied include (non)systematic codes, embedded one-error-correcting codes, and defining sets of codes. A classification of certain mixed perfect codes is also obtained.

Connected through hyperedge HE-1 (induced by source paper "on non full rank perfect codes over finite fields"):
  with members:
    - "on full rank perfect codes over finite fields"
    - "on the structure of non full rank perfect q ary codes"

Connected through hyperedge HE-2 (induced by source paper "on full rank perfect codes over finite fields"):
  with members:
    - "on the structure of non full rank perfect q ary codes"
    - "the perfect binary one error correcting codes of length 15 part i classification"

Connected through hyperedge HE-3 (induced by source paper "propelinear 1 perfect codes from quadratic functions"):
  with members:
    - "z4 linear perfect codes"

Connected through hyperedge HE-4 (induced by source paper "on optimal binary one error correcting codes of lengths 2 m 4 and 2 m 3"):
  with members:
    - "the perfect binary one error correcting codes of length 15 part i classification"
    - "two optimal one error correcting codes of length 13 that are not doubly shortened perfect codes"

Connected through hyperedge HE-5 (induced by source paper "the perfect binary one error correcting codes of length 15 part i classification"):
  with members:
    - "reconstructing extended perfect binary one error correcting codes from their minimum distance graphs"

Connected through hyperedge HE-6 (induced by source paper "two optimal one error correcting codes of length 13 that are not doubly shortened perfect codes"):
  with members:
    - "the perfect binary one error correcting codes of length 15 part i classification"

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)