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: "upper bounds on the size of grain correcting codes"
  Abstract: In this paper, we re-visit the combinatorial error model of Mazumdar et al. that models errors in high-density magnetic recording caused by lack of knowledge of grain boundaries in the recording medium. We present new upper bounds on the cardinality/rate of binary block codes that correct errors within this model.

Connected through hyperedge HE-1 (induced by source paper "linear programming based converses for finite blocklength lossy joint source channel coding"):
  with members:
    - "channels with cost constraints strong converse and dispersion"
    - "generalized sphere packing bound"
    - "correcting grain errors in magnetic media"
    - "non asymptotic upper bounds for deletion correcting codes"
    - "lossy joint source channel coding in the finite blocklength regime"
    - "fixed length lossy compression in the finite blocklength regime"

Connected through hyperedge HE-2 (induced by source paper "generalized sphere packing bound"):
  with members:
    - "bounds for projective codes from semidefinite programming"
    - "correcting grain errors in magnetic media"
    - "non asymptotic upper bounds for deletion correcting codes"
    - "on the non existence of lattice tilings by quasi crosses"
    - "linearity and complements in projective space"
    - "write channel model for bit patterned media recording"
    - "coding for high density recording on a 1 d granular magnetic medium"
    - "coding for errors and erasures in random network coding"

Connected through hyperedge HE-3 (induced by source paper "generalized sphere packing and sphere covering bounds on the size of codes for combinatorial channels"):
  with members:
    - "generalized sphere packing bound"
    - "an improvement to levenshtein s upper bound on the cardinality of deletion correcting codes"
    - "correcting grain errors in magnetic media"

Connected through hyperedge HE-4 (induced by source paper "correcting grain errors in magnetic media"):
  with members:
    - "new constructions of codes for asymmetric channels via concatenation"
    - "non asymptotic upper bounds for deletion correcting codes"
    - "write channel model for bit patterned media recording"
    - "coding for high density recording on a 1 d granular magnetic medium"

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.DM(Discrete Mathematics)