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 "approximation algorithms for polynomial expansion and low density graphs"):
  Abstract: We study the family of intersection graphs of low density objects in low dimensional Euclidean space. This family is quite general, and includes planar graphs. We prove that such graphs have small separators. Next, we present efficient $(1+\varepsilon)$-approximation algorithms for these graphs, for Independent Set, Set Cover, and Dominating Set problems, among others. We also prove corresponding hardness of approximation for some of these optimization problems, providing a characterization of their intractability in terms of density.

Includes members:
  Member "approximation algorithms for low density graphs":
    also connected through other hyperedges:
      (none)
  Member "simple ptas s for families of graphs excluding a minor":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "ptas for steiner tree on map graphs")
  Member "net and prune a linear time algorithm for euclidean distance problems":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "topological data analysis with epsilon net induced lazy witness complex")
  Member "qptas for geometric set cover problems via optimal separators":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "optimal parameterized algorithms for planar facility location problems using voronoi diagrams")
  Member "quasi polynomial time approximation scheme for sparse subsets of polygons":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "efficient approximation schemes for uniform cost clustering problems in planar graphs")
  Member "deciding first order properties of nowhere dense graphs":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "hitting topological minors is fpt")
  Member "approximation schemes for maximum weight independent set of rectangles":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "independent sets of dynamic rectangles algorithms and experiments")
  Member "approximation algorithms for maximum independent set of pseudo disks":
    also connected through other hyperedges:
      - Hyperedge HE-7 (induced by source paper "independent sets of dynamic rectangles algorithms and experiments")

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)