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: "the stackelberg minimum spanning tree game on planar and bounded treewidth graphs"
  Abstract: The Stackelberg Minimum Spanning Tree Game is a two-level combinatorial pricing problem played on a graph representing a network. Its edges are colored either red or blue, and the red edges have a given fixed cost, representing the competitor's prices. The first player chooses an assignment of prices to the blue edges, and the second player then buys the cheapest spanning tree, using any combination of red and blue edges. The goal of the first player is to maximize the total price of purchased blue edges.#R##N##R##N#We study this problem in the cases of planar and bounded-treewidth graphs. We show that the problem is NP-hard on planar graphs but can be solved in polynomial time on graphs of bounded treewidth.

Connected through hyperedge HE-1 (induced by source paper "specializations and generalizations of the stackelberg minimum spanning tree game"):
  with members:
    - "the stackelberg minimum spanning tree game"
    - "stackelberg network pricing is hard to approximate"
    - "improved hardness of approximation for stackelberg shortest path pricing"
    - "stackelberg network pricing games"

Connected through hyperedge HE-2 (induced by source paper "graph pricing problem on bounded treewidth bounded genus and k partite graphs"):
  with members:
    - "approximating sparsest cut in graphs of bounded treewidth"

Connected through hyperedge HE-3 (induced by source paper "stackelberg pricing is hard to approximate within 2 epsilon"):
  with members:
    - "the stackelberg minimum spanning tree game"
    - "stackelberg network pricing is hard to approximate"
    - "improved hardness of approximation for stackelberg shortest path pricing"
    - "stackelberg network pricing games"

Connected through hyperedge HE-4 (induced by source paper "stackelberg network pricing games"):
  with members:
    - "the stackelberg minimum spanning tree game"
    - "improved hardness of approximation for stackelberg shortest path pricing"
    - "algorithmic pricing via virtual valuations"

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.GT(Computer Science and Game Theory)