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: "hardness of approximation for crossing number"
  Abstract: We show that, if P\not=NP, there is a constant c > 1 such that there is no c-approximation algorithm for the crossing number, even when restricted to 3-regular graphs.

Connected through hyperedge HE-1 (induced by source paper "exact crossing number parameterized by vertex cover"):
  with members:
    - "crossing minimization in perturbed drawings"
    - "approximating the rectilinear crossing number"
    - "crossing number for graphs with bounded pathwidth"
    - "parameterized integer quadratic programming variables and coefficients"
    - "adding one edge to planar graphs makes crossing number and 1 planarity hard"
    - "an algorithm for the graph crossing number problem"
    - "computing crossing numbers in quadratic time"

Connected through hyperedge HE-2 (induced by source paper "crossing numbers and stress of random graphs"):
  with members:
    - "approximating the rectilinear crossing number"
    - "crossing number for graphs with bounded pathwidth"
    - "inserting multiple edges into a planar graph"
    - "an algorithm for the graph crossing number problem"

Connected through hyperedge HE-3 (induced by source paper "computational topology of graphs on surfaces"):
  with members:
    - "untangling planar curves"
    - "shortest path embeddings of graphs on surfaces"
    - "a direct proof of the strong hanani tutte theorem on the projective plane"
    - "minimum cycle and homology bases of surface embedded graphs"
    - "crossing number is hard for kernelization"
    - "computing the geometric intersection number of curves"
    - "how to walk your dog in the mountains with no magic leash"
    - "beyond the euler characteristic approximating the genus of general graphs"

Connected through hyperedge HE-4 (induced by source paper "crossing number for graphs with bounded pathwidth"):
  with members:
    - "approximating the rectilinear crossing number"
    - "inserting multiple edges into a planar graph"
    - "an algorithm for the graph crossing number problem"
    - "computing crossing numbers in quadratic time"

Connected through hyperedge HE-5 (induced by source paper "the bundled crossing number"):
  with members:
    - "strict confluent drawing"
    - "an algorithm for the graph crossing number problem"
    - "confluent drawings visualizing non planar diagrams in a planar way"

Connected through hyperedge HE-6 (induced by source paper "inserting multiple edges into a planar graph"):
  with members:
    - "adding one edge to planar graphs makes crossing number and 1 planarity hard"
    - "on graph crossing number and edge planarization"
    - "an algorithm for the graph crossing number problem"
    - "shortest vertex disjoint two face paths in planar graphs"
    - "computing crossing numbers in quadratic time"

Connected through hyperedge HE-7 (induced by source paper "crossing number is hard for kernelization"):
  with members:
    - "fixed parameter tractability of crossing minimization of almost trees"
    - "kernelization lower bounds by cross composition"
    - "computing crossing numbers in quadratic time"

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.CG(Computational Geometry)