human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge is induced by one source paper and its member nodes are the cited papers.

Details of the hypergraph:
Center hyperedge (induced by source paper "obstructions to a small hyperbolicity in helly graphs"):
  Abstract: Abstract   The    δ   -hyperbolicity of a graph is defined by a simple 4-point condition: for any four vertices    u   ,    v   ,    w   , and    x   , the two larger of the distance sums    d   (  u  ,  v  )   +  d   (  w  ,  x  )    ,    d   (  u  ,  w  )   +  d   (  v  ,  x  )    , and    d   (  u  ,  x  )   +  d   (  v  ,  w  )     differ by at most    2  δ  ≥  0   . Hyperbolicity can be viewed as a measure of how close a graph is to a tree metrically; the smaller the hyperbolicity of a graph, the closer it is metrically to a tree. A graph    G    is Helly if its disks satisfy the Helly property, i.e., every family of pairwise intersecting disks in    G    has a common intersection. It is known that for every graph    G    there exists the smallest Helly graph    H   (  G  )     into which    G    isometrically embeds (   H   (  G  )     is called the injective hull of    G   ) and the hyperbolicity of    H   (  G  )     is equal to the hyperbolicity of    G   . Motivated by this, we investigate structural properties of Helly graphs that govern their hyperbolicity and identify three isometric subgraphs of the King-grid as structural obstructions to a small hyperbolicity in Helly graphs.

Includes members:
  Member "fast approximation algorithms for p centres in large delta hyperbolic graphs":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "fast approximation of centrality and distances in hyperbolic graphs")
  Member "core congestion is inherent in hyperbolic networks":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "eccentricity terrain of delta hyperbolic graphs")
  Member "node expansions and cuts in gromov hyperbolic graphs":
    also connected through other hyperedges:
      (none)
  Member "polynomial bounds for the grid minor theorem":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "hitting topological minors is fpt")
  Member "on the hyperbolicity of small world and tree like random graphs":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "a geometric approach for real time monitoring of dynamic large scale graphs as level graphs illustrated")
  Member "euclidean versus hyperbolic congestion in idealized versus experimental networks":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "why did the shape of your network change on detecting network anomalies via non local curvatures")

Question: Please tell me which class the source paper 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.DS(Data Structures and Algorithms)