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 ptas for minimum makespan vehicle routing in trees"
  Abstract: We consider a variant of the vehicle routing problem on trees in which the goal is to route a fleet of vehicles to serve a set of clients so that the makespan, the longest distance traveled by one of the vehicles, is minimized. This is referred to as the Minimum Makespan Vehicle Routing problem on trees. We present a polynomial time approximation scheme (PTAS) for this problem. Our main insight is that we can restrict the set of potential solutions without adding too much to the optimal makespan. This simplification relies on partitioning the tree into clusters such that there exists a near-optimal solution in which every tour that visits a given cluster takes on one of a few forms. In particular, there are at most two tours serving clients in any cluster. Our dyamic program then finds a near-optimal set of tours using these simple building blocks within each cluster rather than making decisions for covering each leaf in the tree. This limits the amount of rounding error incurred by the dynamic program, yielding the PTAS.

Connected through hyperedge HE-1 (induced by source paper "a constant factor approximation for capacitated min max tree cover"):
  with members:
    - "a ptas for bounded capacity vehicle routing in planar graphs"
    - "iterative partial rounding for vertex cover with hard capacities"
    - "tight algorithms for vertex cover with hard capacities on multigraphs and hypergraphs"
    - "an approximation algorithm for uniform capacitated k median problem with 1 epsilon capacity violation"
    - "a new approximation technique for resource allocation problems"

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.DS(Data Structures and Algorithms)