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 density of fan planar graphs"
  Abstract: A topological drawing of a graph is fan-planar if for each edge e the edges crossing e have a common endpoint on the same side of e, and a fan-planar graph is a graph admitting such a drawing. Equivalently, this can be formulated by two forbidden patterns, one of which is the configuration where e is crossed by two independent edges and the other where e is crossed by incident edges with the common endpoint on different sides of e. In particular every edge of a fan-planar graph is crossed only by the edges of a star. A topological drawing is simple if any two edges have at most one point in common. #R##N#The class of fan-planar graphs is a natural variant of other classes defined by forbidden intersection patterns in a topological drawing of the graph. So every 1-planar graph is also fan-planar, and every fan-planar graph is also quasiplanar, where both inclusions are strict. Fan-planar graphs also fit perfectly in a recent series of work on nearly-planar graphs from the area of graph drawing and combinatorial embeddings. #R##N#For topologically defined graph classes, one of the most fundamental questions asks for the maximum number of edges in any such graph with n vertices. We prove that every n-vertex graph without loops and parallel edges that admits a simple fan-planar drawig has at most 5n-10 edges and that this bound is tight for every n >= 20. #R##N#Furthermore we discuss possible extensions and generalizations of these new concepts.

Connected through hyperedge HE-1 (induced by source paper "fan crossing free graphs"):
  with members:
    - "efficient generation of different topological representations of graphs beyond planarity"
    - "simple k planar graphs are simple k 1 quasiplanar"
    - "a survey on graph drawing beyond planarity"
    - "recognizing optimal 1 planar graphs in linear time"
    - "t shape visibility representations of 1 planar graphs"
    - "nic planar graphs"
    - "on fan crossing graphs"
    - "an annotated bibliography on 1 planarity"

Connected through hyperedge HE-2 (induced by source paper "on layered fan planar graph drawings"):
  with members:
    - "a survey on graph drawing beyond planarity"
    - "an annotated bibliography on 1 planarity"

Connected through hyperedge HE-3 (induced by source paper "efficient generation of different topological representations of graphs beyond planarity"):
  with members:
    - "a survey on graph drawing beyond planarity"
    - "minimum weight connectivity augmentation for planar straight line graphs"
    - "1 fan bundle planar drawings of graphs"
    - "visibility representations of boxes in 2 5 dimensions"
    - "topological drawings of complete bipartite graphs"
    - "on the recognition of fan planar and maximal outer fan planar graphs"
    - "on the number of edges of fan crossing free graphs"
    - "progress on partial edge drawings"

Connected through hyperedge HE-4 (induced by source paper "simple k planar graphs are simple k 1 quasiplanar"):
  with members:
    - "a survey on graph drawing beyond planarity"
    - "on optimal 2 and 3 planar graphs"
    - "on the relationship between k planar and k quasi planar graphs"
    - "two planar graphs are quasiplanar"
    - "on the density of non simple 3 planar graphs"
    - "recognizing and drawing ic planar graphs"
    - "on the number of edges of fan crossing free graphs"

Connected through hyperedge HE-5 (induced by source paper "crossing numbers of beyond planar graphs"):
  with members:
    - "a survey on graph drawing beyond planarity"
    - "an annotated bibliography on 1 planarity"

Connected through hyperedge HE-6 (induced by source paper "a survey on graph drawing beyond planarity"):
  with members:
    - "parameterized complexity of 1 planarity"
    - "minimum weight connectivity augmentation for planar straight line graphs"
    - "compact drawings of 1 planar graphs with right angle crossings and few bends"
    - "drawing subcubic 1 planar graphs with few bends few slopes and large angles"
    - "turning cliques into paths to achieve planarity"
    - "a heuristic approach towards drawings of graphs with high crossing resolution"
    - "on rac drawings of graphs with one bend per edge"
    - "recognizing optimal 1 planar graphs in linear time"

Connected through hyperedge HE-7 (induced by source paper "minimum weight connectivity augmentation for planar straight line graphs"):
  with members:
    - "on the relationship between k planar and k quasi planar graphs"
    - "an annotated bibliography on 1 planarity"
    - "crossing patterns in nonplanar road networks"
    - "two planar graphs are quasiplanar"
    - "on the density of non simple 3 planar graphs"
    - "recognizing and drawing ic planar graphs"
    - "a simplified 1 5 approximation algorithm for augmenting edge connectivity of a graph from 1 to 2"
    - "on the recognition of fan planar and maximal outer fan planar graphs"

Connected through hyperedge HE-8 (induced by source paper "on rac drawings of graphs with one bend per edge"):
  with members:
    - "a survey on graph drawing beyond planarity"
    - "nic planar graphs"
    - "on the density of non simple 3 planar graphs"
    - "recognizing and drawing ic planar graphs"
    - "on the number of edges of fan crossing free graphs"
    - "the straight line rac drawing problem is np 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)