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: "computing a minimum dilation spanning tree is np hard"
  Abstract: In a geometric network G = (S, E), the graph distance between two vertices u, v in S is the length of the shortest path in G connecting u to v. The dilation of G is the maximum factor by which the graph distance of a pair of vertices differs from their Euclidean distance. We show that given a set S of n points with integer coordinates in the plane and a rational dilation delta > 1, it is NP-hard to determine whether a spanning tree of S with dilation at most delta exists.

Connected through hyperedge HE-1 (induced by source paper "on the stretch factor of polygonal chains"):
  with members:
    - "self approaching paths in simple polygons"
    - "self approaching graphs"
    - "on range searching with semialgebraic sets ii"
    - "beta skeletons have unbounded dilation"

Connected through hyperedge HE-2 (induced by source paper "lower bounds on the dilation of plane spanners"):
  with members:
    - "degree four plane spanners simpler and better"
    - "the stretch factor of the delaunay triangulation is less than 1 998"
    - "on geometric spanners of euclidean and unit disk graphs"
    - "sparse geometric graphs with small dilation"

Connected through hyperedge HE-3 (induced by source paper "single source dilation bounded minimum spanning trees"):
  with members:
    - "minimum dilation stars"

Connected through hyperedge HE-4 (induced by source paper "optimal embedding into star metrics"):
  with members:
    - "minimum dilation stars"

Connected through hyperedge HE-5 (induced by source paper "sparse geometric graphs with small dilation"):
  with members:
    - "minimum dilation stars"

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)