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: "rainbow colouring of split and threshold graphs"
  Abstract: A rainbow colouring of a connected graph is a colouring of the edges of the graph, such that every pair of vertices is connected by at least one path in which no two edges are coloured the same. Such a colouring using minimum possible number of colours is called an optimal rainbow colouring, and the minimum number of colours required is called the rainbow connection number of the graph. In this article, we show the following: #R##N#1. The problem of deciding whether a graph can be rainbow coloured using 3 colours remains NP-complete even when restricted to the class of split graphs. However, any split graph can be rainbow coloured in linear time using at most one more colour than the optimum. #R##N#2. For every integer k larger than 2, the problem of deciding whether a graph can be rainbow coloured using k colours remains NP-complete even when restricted to the class of chordal graphs. #R##N#3. For every positive integer k, threshold graphs with rainbow connection number k can be characterised based on their degree sequence alone. Further, we can optimally rainbow colour a threshold graph in linear time.

Connected through hyperedge HE-1 (induced by source paper "algorithms and bounds for very strong rainbow coloring"):
  with members:
    - "on the fine grained complexity of rainbow coloring"
    - "further hardness results on rainbow and strong rainbow connectivity"
    - "on the complexity of rainbow coloring problems"
    - "computing minimum rainbow and strong rainbow colorings of block graphs"

Connected through hyperedge HE-2 (induced by source paper "on the fine grained complexity of rainbow coloring"):
  with members:
    - "on the complexity of rainbow coloring problems"
    - "tight lower bound for the channel assignment problem"
    - "rainbow colouring of split graphs"

Connected through hyperedge HE-3 (induced by source paper "on the complexity of rainbow coloring problems"):
  with members:
    - "further hardness results on rainbow and strong rainbow connectivity"

Connected through hyperedge HE-4 (induced by source paper "computing minimum rainbow and strong rainbow colorings of block graphs"):
  with members:
    - "further hardness results on rainbow and strong rainbow connectivity"
    - "rainbow colouring of split graphs"
    - "note on the complexity of deciding the rainbow connectedness for bipartite 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)