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: "optimal local routing on delaunay triangulations defined by empty equilateral triangles"
  Abstract: We present a deterministic local routing algorithm that is guaranteed to find a path between any pair of vertices in a half-$\theta_6$-graph (the half-$\theta_6$-graph is equivalent to the Delaunay triangulation where the empty region is an equilateral triangle). The length of the path is at most $5/\sqrt{3} \approx 2.887$ times the Euclidean distance between the pair of vertices. Moreover, we show that no local routing algorithm can achieve a better routing ratio, thereby proving that our routing algorithm is optimal. This is somewhat surprising because the spanning ratio of the half-$\theta_6$-graph is 2, meaning that even though there always exists a path whose lengths is at most twice the Euclidean distance, we cannot always find such a path when routing locally. #R##N#Since every triangulation can be embedded in the plane as a half-$\theta_6$-graph using $O(\log n)$ bits per vertex coordinate via Schnyder's embedding scheme (SODA 1990), our result provides a competitive local routing algorithm for every such embedded triangulation. Finally, we show how our routing algorithm can be adapted to provide a routing ratio of $15/\sqrt{3} \approx 8.660$ on two bounded degree subgraphs of the half-$\theta_6$-graph.

Connected through hyperedge HE-1 (induced by source paper "routing in histograms"):
  with members:
    - "plane hop spanners for unit disk graphs simpler and better"
    - "routing in unit disk graphs"
    - "routing in polygonal domains"
    - "constant approximation algorithms for guarding simple polygons using vertex guards"
    - "new routing techniques and their applications"
    - "competitive local routing with constraints"
    - "approximability of guarding weak visibility polygons"

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"
    - "the θ 5 graph is a spanner"
    - "theta 3 is connected"
    - "towards tight bounds on theta graphs"

Connected through hyperedge HE-3 (induced by source paper "local routing in sparse and lightweight geometric graphs"):
  with members:
    - "gabriel triangulations and angle monotone graphs local routing and recognition"
    - "the stretch factor of the delaunay triangulation is less than 1 998"

Connected through hyperedge HE-4 (induced by source paper "angle monotone graphs construction and local routing"):
  with members:
    - "angle monotone paths in non obtuse triangulations"
    - "gabriel triangulations and angle monotone graphs local routing and recognition"
    - "increasing chord graphs on point sets"
    - "on the stretch factor of convex delaunay graphs"

Connected through hyperedge HE-5 (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"
    - "new routing techniques and their applications"
    - "competitive local routing with constraints"
    - "new and improved spanning ratios for yao graphs"

Connected through hyperedge HE-6 (induced by source paper "on plane constrained bounded degree spanners"):
  with members:
    - "constrained generalized delaunay graphs are plane spanners"
    - "upper bounds on the spanning ratio of constrained theta graphs"

Connected through hyperedge HE-7 (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"
    - "on the stretch factor of the theta 4 graph"

Connected through hyperedge HE-8 (induced by source paper "gabriel triangulations and angle monotone graphs local routing and recognition"):
  with members:
    - "lower bounds on the dilation of plane spanners"
    - "increasing chord graphs on point sets"
    - "the stretch factor of the delaunay triangulation is less than 1 998"
    - "self approaching graphs"

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)