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: "recognizing optimal 1 planar graphs in linear time"
  Abstract: A graph with n vertices is 1-planar if it can be drawn in the plane such that each edge is crossed at most once, and is optimal if it has the maximum of \(4n-8\) edges. We show that optimal 1-planar graphs can be recognized in linear time. Our algorithm implements a graph reduction system with two rules, which can be used to reduce every optimal 1-planar graph to an irreducible extended wheel graph. The graph reduction system is non-deterministic, constraint, and non-confluent.

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"
    - "t shape visibility representations of 1 planar graphs"
    - "nic planar graphs"
    - "on fan crossing graphs"
    - "an annotated bibliography on 1 planarity"
    - "recognizing and drawing ic planar graphs"

Connected through hyperedge HE-2 (induced by source paper "an experimental study of a 1 planarity testing and embedding algorithm"):
  with members:
    - "planar graphs have bounded queue number"
    - "a survey on graph drawing beyond planarity"
    - "parameterized complexity of 1 planarity"
    - "embedding preserving rectangle visibility representations of nonplanar graphs"
    - "an annotated bibliography on 1 planarity"
    - "crossing patterns in nonplanar road networks"
    - "re embedding a 1 plane graph into a straight line drawing in linear time"
    - "ortho polygon visibility representations of embedded graphs"

Connected through hyperedge HE-3 (induced by source paper "packing trees into 1 planar graphs"):
  with members:
    - "a survey on graph drawing beyond planarity"
    - "an annotated bibliography on 1 planarity"
    - "the planar tree packing theorem"

Connected through hyperedge HE-4 (induced by source paper "map graphs having witnesses of large girth"):
  with members:
    - "hardness and structural results for half squares of restricted tree convex bipartite graphs"
    - "nic planar graphs"
    - "bidimensionality and geometric graphs"

Connected through hyperedge HE-5 (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"
    - "orthogonal and smooth orthogonal layouts of 1 planar graphs with low edge complexity"

Connected through hyperedge HE-6 (induced by source paper "t shape visibility representations of 1 planar graphs"):
  with members:
    - "nic planar graphs"
    - "an annotated bibliography on 1 planarity"
    - "recognizing and drawing ic planar graphs"
    - "ortho polygon visibility representations of embedded graphs"
    - "simultaneous visibility representations of plane st graphs using l shapes"
    - "on 4 map graphs and 1 planar graphs and their recognition problem"
    - "l visibility drawings of ic planar graphs"
    - "1 visibility representations of 1 planar graphs"

Connected through hyperedge HE-7 (induced by source paper "an annotated bibliography on 1 planarity"):
  with members:
    - "parameterized complexity of 1 planarity"
    - "nic planar graphs"
    - "new results on edge partitions of 1 plane graphs"
    - "recognizing and drawing ic planar graphs"
    - "re embedding a 1 plane graph into a straight line drawing in linear time"
    - "recognizing ic planar and nic planar graphs"
    - "ortho polygon visibility representations of embedded graphs"
    - "approximation algorithms for polynomial expansion and low density graphs"

Connected through hyperedge HE-8 (induced by source paper "beyond planarity density results for bipartite graphs"):
  with members:
    - "on the relationship between k planar and k quasi planar graphs"
    - "an annotated bibliography on 1 planarity"
    - "two planar graphs are quasiplanar"
    - "on the density of non simple 3 planar graphs"
    - "recognizing and drawing ic planar graphs"
    - "on the recognition of fan planar and maximal outer fan planar graphs"
    - "the density of fan planar graphs"
    - "on the number of edges of fan crossing free 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)