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: "being fat and friendly is not enough"
  Abstract: We show that there is no $(1+\eps)$-approximation algorithm for the problem of covering points in the plane by minimum number of fat triangles of similar size (with the minimum angle of the triangles being close to 45 degrees). Here, the available triangles are prespecified in advance. Since a constant factor approximation algorithm is known for this problem \cite{cv-iaags-07}, this settles the approximability of this problem. #R##N#We also investigate some related problems, including cover by friendly fat shapes, and independent set of triangles in three dimensions.

Connected through hyperedge HE-1 (induced by source paper "approximation schemes for independent set and sparse subsets of polygons"):
  with members:
    - "on approximating maximum independent set of rectangles"
    - "optimal parameterized algorithms for planar facility location problems using voronoi diagrams"
    - "shortest path in a polygon using sublinear space"
    - "approximation schemes for partitioning convex decomposition and surface approximation"
    - "a qptas for the base of the number of triangulations of a planar point set"
    - "quasi polynomial time approximation scheme for sparse subsets of polygons"
    - "a qptas for maximum weight independent set of polygons with polylogarithmically many vertices"
    - "approximation schemes for maximum weight independent set of rectangles"

Connected through hyperedge HE-2 (induced by source paper "optimal parameterized algorithms for planar facility location problems using voronoi diagrams"):
  with members:
    - "the limited blessing of low dimensionality when 1 1 d is the best possible exponent for d dimensional geometric problems"
    - "qptas for geometric set cover problems via optimal separators"
    - "quasi polynomial time approximation scheme for sparse subsets of polygons"
    - "a qptas for maximum weight independent set of polygons with polylogarithmically many vertices"
    - "network sparsification for steiner problems on planar and bounded genus graphs"
    - "approximation schemes for maximum weight independent set of rectangles"
    - "kernelization of packing problems"
    - "k gap interval graphs"

Connected through hyperedge HE-3 (induced by source paper "approximation algorithms for polynomial expansion and low density graphs"):
  with members:
    - "approximation algorithms for low density graphs"
    - "simple ptas s for families of graphs excluding a minor"
    - "net and prune a linear time algorithm for euclidean distance problems"
    - "qptas for geometric set cover problems via optimal separators"
    - "quasi polynomial time approximation scheme for sparse subsets of polygons"
    - "deciding first order properties of nowhere dense graphs"
    - "approximation schemes for maximum weight independent set of rectangles"
    - "approximation algorithms for maximum independent set of pseudo disks"

Connected through hyperedge HE-4 (induced by source paper "approximation algorithms for low density graphs"):
  with members:
    - "simple ptas s for families of graphs excluding a minor"
    - "net and prune a linear time algorithm for euclidean distance problems"
    - "qptas for geometric set cover problems via optimal separators"
    - "quasi polynomial time approximation scheme for sparse subsets of polygons"
    - "approximation schemes for maximum weight independent set of rectangles"
    - "approximation algorithms for maximum independent set of pseudo disks"
    - "a simple proof of the existence of a planar separator"
    - "improved approximation algorithms for geometric set cover"

Connected through hyperedge HE-5 (induced by source paper "qptas for geometric set cover problems via optimal separators"):
  with members:
    - "quasi polynomial time approximation scheme for sparse subsets of polygons"
    - "a qptas for maximum weight independent set of polygons with polylogarithmically many vertices"
    - "approximation schemes for maximum weight independent set of rectangles"

Connected through hyperedge HE-6 (induced by source paper "quasi polynomial time approximation scheme for sparse subsets of polygons"):
  with members:
    - "qptas for geometric set cover problems via optimal separators"
    - "approximation schemes for maximum weight independent set of rectangles"
    - "approximation algorithms for maximum independent set of pseudo disks"
    - "a simple proof of the existence of a planar separator"
    - "geometric packing under non uniform constraints"

Connected through hyperedge HE-7 (induced by source paper "geometric packing under non uniform constraints"):
  with members:
    - "approximation algorithms for maximum independent set of pseudo disks"
    - "on the set multi cover problem in geometric settings"

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)