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: "inefficiencies in network models a graph theoretic perspective"
  Abstract: Abstract   We consider three network models where information items flow from a source to a sink node: flow networks, depletable channels, and traffic networks. We start with the standard model of flow networks; we characterise graph topologies that admit non-maximum saturating flows, under some capacity-to-edge assignment. We then consider a model where routing is constrained by energy available on nodes in finite supply (like in Smartdust) and efficiency is related to energy consumption and again to maximality of saturating flows. Finally, we consider a traffic model for selfish routing, where efficiency is related to latency at a Wardrop equilibrium. We show that all these forms of inefficiency yield different classes of graphs (apart from in the acyclic case, where the first and the last forms generate the same class). Interestingly, in all cases inefficient graphs can be made efficient by removing edges; this resembles a well-known phenomenon, called Braess's paradox.

Connected through hyperedge HE-1 (induced by source paper "negative prices in network pricing games"):
  with members:
    - "toll caps in privatized road networks"
    - "approximate revenue maximization with multiple items"
    - "matroids are immune to braess paradox"
    - "new complexity results and algorithms for the minimum tollbooth problem"
    - "stackelberg shortest path tree game revisited"
    - "the stackelberg minimum spanning tree game"
    - "stackelberg network pricing is hard to approximate"
    - "improved hardness of approximation for stackelberg shortest path pricing"

Connected through hyperedge HE-2 (induced by source paper "a characterization of undirected graphs admitting optimal cost shares"):
  with members:
    - "designing networks with good equilibria under uncertainty"
    - "an h n 2 upper bound on the price of stability of undirected network design games"
    - "sharing non anonymous costs of multiple resources optimally"
    - "potential games are necessary to ensure pure nash equilibria in cost sharing games"
    - "resource buying games"
    - "an o lognloglogn upper bound on the price of stability for undirected shapley network design games"

Connected through hyperedge HE-3 (induced by source paper "a polynomial time algorithm for detecting the possibility of braess paradox in directed graphs"):
  with members:
    - "matroids are immune to braess paradox"

Connected through hyperedge HE-4 (induced by source paper "matroids are immune to braess paradox"):
  with members:
    - "resource competition on integral polymatroids"
    - "resource buying games"

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)