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: "the θ 5 graph is a spanner"
  Abstract: Given a set of points in the plane, we show that the ?-graph with 5 cones is a geometric spanner with spanning ratio at most 50 + 22 5 ? 9.960 . This is the first constant upper bound on the spanning ratio of this graph. The upper bound uses a constructive argument that gives a (possibly self-intersecting) path between any two vertices, of length at most 50 + 22 5 times the Euclidean distance between the vertices. We also give a lower bound on the spanning ratio of 1 2 ( 11 5 - 17 ) ? 3.798 .

Connected through hyperedge HE-1 (induced by source paper "maximum matchings and minimum blocking sets in θ 6 graphs"):
  with members:
    - "spanning properties of theta theta 6"
    - "on the spanning and routing ratio of theta four"
    - "higher order triangular distance delaunay graphs graph theoretical properties"
    - "on the average number of edges in theta graphs"
    - "fixed orientation equilateral triangle matching of point sets"
    - "witness gabriel graphs"
    - "witness delaunay graphs"

Connected through hyperedge HE-2 (induced by source paper "expected complexity of routing in theta 6 and half theta 6 graphs"):
  with members:
    - "on the spanning and routing ratio of theta four"
    - "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 "spanning properties of theta theta 6"):
  with members:
    - "on the spanning and routing ratio of theta four"
    - "odd yao yao graphs are not spanners"
    - "almost all even yao yao graphs are spanners"
    - "towards tight bounds on theta graphs"
    - "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-4 (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"
    - "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"
    - "new and improved spanning ratios for yao graphs"

Connected through hyperedge HE-5 (induced by source paper "the price of order"):
  with members:
    - "theta 3 is connected"
    - "towards tight bounds on theta graphs"
    - "optimal local routing on delaunay triangulations defined by empty equilateral triangles"
    - "on the stretch factor of the theta 4 graph"

Connected through hyperedge HE-6 (induced by source paper "spanning properties of theta theta graphs"):
  with members:
    - "towards tight bounds on theta graphs"
    - "the yao graph y_5 is a spanner"
    - "new and improved spanning ratios for yao graphs"
    - "on the stretch factor of the theta 4 graph"
    - "an infinite class of sparse yao spanners"
    - "π 2 angle yao graphs are spanners"

Connected through hyperedge HE-7 (induced by source paper "theta 3 is connected"):
  with members:
    - "on the stretch factor of the theta 4 graph"
    - "undirected connectivity of sparse yao graphs"

Connected through hyperedge HE-8 (induced by source paper "towards tight bounds on theta graphs"):
  with members:
    - "theta 3 is connected"
    - "on the stretch factor of the theta 4 graph"

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)