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: "energy efficient delivery by heterogeneous mobile agents"
  Abstract: We consider the problem of delivering $m$ messages between specified source-target pairs in a weighted undirected graph, by $k$ mobile agents initially located at distinct nodes of the graph. Each agent consumes energy proportional to the distance it travels in the graph and we are interested in optimizing the total energy consumption for the team of agents. Unlike previous related work, we consider heterogeneous agents with different rates of energy consumption (weights~$w_i$). To solve the delivery problem, agents face three major challenges: \emph{Collaboration} (how to work together on each message), \emph{Planning} (which route to take) and \emph{Coordination} (how to assign agents to messages). #R##N#We first show that the delivery problem can be 2-approximated \emph{without} collaborating and that this is best possible, i.e., we show that the \emph{benefit of collaboration} is 2 in general. We also show that the benefit of collaboration for a single message is~$1/\ln 2 \approx 1.44$. Planning turns out to be \NP-hard to approximate even for a single agent, but can be 2-approximated in polynomial time if agents have unit capacities and do not collaborate. We further show that coordination is \NP-hard even for agents with unit capacity, but can be efficiently solved exactly if they have uniform weights. Finally, we give a polynomial-time $(4\max\tfrac{w_i}{w_j})$-approximation for message delivery with unit capacities.

Connected through hyperedge HE-1 (induced by source paper "an efficient algorithm for the fast delivery problem"):
  with members:
    - "collective fast delivery by energy efficient agents"
    - "collaborative delivery with energy constrained mobile robots"

Connected through hyperedge HE-2 (induced by source paper "collaborative delivery with energy constrained mobile robots"):
  with members:
    - "convergecast and broadcast by power aware mobile agents"

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)