human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge is induced by one source paper and its member nodes are the cited papers.

Details of the hypergraph:
Center hyperedge (induced by source paper "unsolved problems in visibility graphs of points segments and polygons"):
  Abstract: In this survey paper, we present open problems and conjectures on visibility graphs of points, segments and polygons along with necessary backgrounds for understanding them.

Includes members:
  Member "convex obstacle numbers of outerplanar graphs and bipartite permutation graphs":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "obstructing visibilities with one obstacle")
  Member "a new upper bound for the vc dimension of visibility regions":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "the parameterized complexity of guarding almost convex polygons")
  Member "some results on point visibility graphs":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "pseudo triangle visibility graph characterization and reconstruction")
  Member "improved approximation for guarding simple galleries from the perimeter":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "the parameterized complexity of guarding almost convex polygons")

Question: Please tell me which class the source paper 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)