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: "on the stretch factor of the theta 4 graph"
  Abstract: In this paper we show that the \theta-graph with 4 cones has constant stretch factor, i.e., there is a path between any pair of vertices in this graph whose length is at most a constant times the Euclidean distance between that pair of vertices. This is the last \theta-graph for which it was not known whether its stretch factor was bounded.

Connected through hyperedge HE-1 (induced by source paper "routing in polygonal domains"):
  with members:
    - "routing in unit disk graphs"
    - "routing on the visibility graph"
    - "constrained routing between non visible vertices"
    - "the θ 5 graph is a spanner"
    - "towards tight bounds on theta graphs"
    - "optimal local routing on delaunay triangulations defined by empty equilateral triangles"
    - "new routing techniques and their applications"
    - "competitive local routing with constraints"

Connected through hyperedge HE-2 (induced by source paper "the price of order"):
  with members:
    - "the θ 5 graph is a spanner"
    - "theta 3 is connected"
    - "towards tight bounds on theta graphs"
    - "optimal local routing on delaunay triangulations defined by empty equilateral triangles"

Connected through hyperedge HE-3 (induced by source paper "the θ 5 graph is a spanner"):
  with members:
    - "new and improved spanning ratios for yao graphs"
    - "on the average number of edges in theta graphs"
    - "π 2 angle yao graphs are spanners"

Connected through hyperedge HE-4 (induced by source paper "spanning properties of theta theta graphs"):
  with members:
    - "the θ 5 graph is a spanner"
    - "towards tight bounds on theta graphs"
    - "the yao graph y_5 is a spanner"
    - "new and improved spanning ratios for yao graphs"
    - "an infinite class of sparse yao spanners"
    - "π 2 angle yao graphs are spanners"

Connected through hyperedge HE-5 (induced by source paper "theta 3 is connected"):
  with members:
    - "the θ 5 graph is a spanner"
    - "undirected connectivity of sparse yao graphs"

Connected through hyperedge HE-6 (induced by source paper "towards tight bounds on theta graphs"):
  with members:
    - "the θ 5 graph is a spanner"
    - "theta 3 is connected"

Connected through hyperedge HE-7 (induced by source paper "on the average number of edges in theta graphs"):
  with members:
    - "the θ 5 graph is a spanner"
    - "probabilistic bounds on the length of a longest edge in delaunay graphs of random points in d dimensions"
    - "on the expected maximum degree of gabriel and yao graphs"

Connected through hyperedge HE-8 (induced by source paper "kinetic data structures for the semi yao graph and all nearest neighbors in r d"):
  with members:
    - "the θ 5 graph is a spanner"
    - "on topological changes in the delaunay triangulation of moving points"

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)