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: "two page book embeddings of 4 planar graphs"
  Abstract: Back in the Eighties, Heath showed that every 3-planar graph is subhamiltonian and asked whether this result can be extended to a class of graphs of degree greater than three. In this paper we affirmatively answer this question for the class of 4-planar graphs. Our contribution consists of two algorithms: The first one is limited to triconnected graphs, but runs in linear time and uses existing methods for computing hamiltonian cycles in planar graphs. The second one, which solves the general case of the problem, is a quadratic-time algorithm based on the book-embedding viewpoint of the problem.

Connected through hyperedge HE-1 (induced by source paper "upward book embeddings of st graphs"):
  with members:
    - "upward planar morphs"
    - "windrose planarity embedding graphs with direction constrained edges"
    - "crossing minimization for 1 page and 2 page drawings of graphs with bounded treewidth"
    - "upward partitioned book embeddings"
    - "planar l drawings of directed graphs"
    - "arc diagrams flip distances and hamiltonian triangulations"
    - "the book thickness of 1 planar graphs is constant"
    - "intersection link representations of graphs"

Connected through hyperedge HE-2 (induced by source paper "parameterized algorithms for book embedding problems"):
  with members:
    - "parameterized complexity of 1 planarity"
    - "crossing minimization for 1 page and 2 page drawings of graphs with bounded treewidth"
    - "the complexity landscape of decompositional parameters for ilp"

Connected through hyperedge HE-3 (induced by source paper "upward partitioned book embeddings"):
  with members:
    - "advancements on sefe and partitioned book embedding problems"
    - "implementing a partitioned 2 page book embedding testing algorithm"
    - "when can you fold a map"

Connected through hyperedge HE-4 (induced by source paper "simultaneous drawing of planar graphs with right angle crossings and few bends"):
  with members:
    - "simultaneous embedding edge orderings relative positions cutvertices"
    - "simultaneous embedding of planar graphs"
    - "testing simultaneous planarity when the common graph is 2 connected"
    - "on a tree and a path with no geometric simultaneous embedding"
    - "simultaneous embedding of a planar graph and its dual on the grid"

Connected through hyperedge HE-5 (induced by source paper "fractals for kernelization lower bounds"):
  with members:
    - "the parameterized complexity of the minimum shared edges problem"
    - "interdiction problems on planar graphs"
    - "kernelization lower bounds by cross composition"
    - "clique cover and graph separation new incompressibility results"

Connected through hyperedge HE-6 (induced by source paper "fractals for kernelization lower bounds with an application to length bounded cut problems"):
  with members:
    - "interdiction problems on planar graphs"
    - "kernelization lower bounds by cross composition"

Connected through hyperedge HE-7 (induced by source paper "the book thickness of 1 planar graphs is constant"):
  with members:
    - "adding one edge to planar graphs makes crossing number and 1 planarity hard"

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)