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: "a quasi polynomial time approximation scheme for euclidean capacitated vehicle routing"
  Abstract: In the capacitated vehicle routing problem, introduced by Dantzig and Ramser in 1959, we are given the locations of n customers and a depot, along with a vehicle of capacity k, and wish to find a minimum length collection of tours, each starting from the depot and visiting at most k customers, whose union covers all the customers. We give a quasi-polynomial time approximation scheme for the setting where the customers and the depot are on the plane, and distances are given by the Euclidean metric.

Connected through hyperedge HE-1 (induced by source paper "a ptas for bounded capacity vehicle routing in planar graphs"):
  with members:
    - "a tight 4 3 approximation for capacitated vehicle routing in trees"
    - "a framework for vehicle routing approximation schemes in trees"
    - "a 1 varepsilon embedding of low highway dimension graphs into bounded treewidth graphs"
    - "polynomial time approximation schemes for k center and bounded capacity vehicle routing in metrics with bounded highway dimension"

Connected through hyperedge HE-2 (induced by source paper "a tight 4 3 approximation for capacitated vehicle routing in trees"):
  with members:
    - "polynomial time approximation schemes for k center and bounded capacity vehicle routing in metrics with bounded highway dimension"

Connected through hyperedge HE-3 (induced by source paper "polynomial time approximation schemes for k center and bounded capacity vehicle routing in metrics with bounded highway dimension"):
  with members:
    - "fixed parameter approximations for k center problems in low highway dimension graphs"
    - "approximating k median via pseudo approximation"
    - "ptas for k tour cover problem on the plane for moderately large values of k"

Connected through hyperedge HE-4 (induced by source paper "towards asymptotically optimal one to one pdp algorithms for capacity 2 vehicles"):
  with members:
    - "asymptotically optimal algorithms for one to one pickup and delivery problems with applications to transportation systems"

Connected through hyperedge HE-5 (induced by source paper "capacitated vehicle routing with non uniform speeds"):
  with members:
    - "balancing minimum spanning trees and shortest path trees"

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.DM(Discrete Mathematics)