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: "on disjoint matchings in cubic graphs maximum 2 edge colorable and maximum 3 edge colorable subgraphs"
  Abstract: Abstract   We show that any 2-factor of a cubic graph can be extended to a maximum 3-edge-colorable subgraph. We also show that the sum of sizes of maximum 2- and 3-edge-colorable subgraphs of a cubic graph is at least twice of its number of vertices. Finally, for a cubic graph    G   , consider the pairs of edge-disjoint matchings whose union consists of as many edges as possible. Let    H    be the largest matching among such pairs. Let    M    be a maximum matching of    G   . We show that    9  /  8    is a tight upper bound for     |  M  |   /   |  H  |    .

Connected through hyperedge HE-1 (induced by source paper "on the fixed parameter tractability of the maximum 2 edge colorable subgraph problem"):
  with members:
    - "on maximum k edge colorable subgraphs of bipartite graphs"
    - "beyond the vizing s bound for at most seven colors"
    - "on disjoint matchings in cubic graphs"

Connected through hyperedge HE-2 (induced by source paper "on maximum k edge colorable subgraphs of bipartite graphs"):
  with members:
    - "beyond the vizing s bound for at most seven colors"
    - "on disjoint matchings in cubic graphs"
    - "on parsimonious edge colouring of graphs with maximum degree three"

Connected through hyperedge HE-3 (induced by source paper "graphs disjoint matchings and some inequalities"):
  with members:
    - "beyond the vizing s bound for at most seven colors"
    - "on disjoint matchings in cubic graphs"
    - "on parsimonious edge colouring of graphs with maximum degree three"

Connected through hyperedge HE-4 (induced by source paper "on strongly spanning k edge colorable subgraphs"):
  with members:
    - "on disjoint matchings in cubic graphs"

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)