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: "improved bounds for the excluded grid theorem"
  Abstract: We study the Excluded Grid Theorem of Robertson and Seymour. This is a fundamental result in graph theory, that states that there is some function $f: Z^+\rightarrow Z^+$, such that for all integers $g>0$, every graph of treewidth at least $f(g)$ contains the $(g\times g)$-grid as a minor. Until recently, the best known upper bounds on $f$ were super-exponential in $g$. A recent work of Chekuri and Chuzhoy provided the first polynomial bound, by showing that treewidth $f(g)=O(g^{98}\operatorname{poly}\log g)$ is sufficient to ensure the existence of the $(g\times g)$-grid minor in any graph. In this paper we improve this bound to $f(g)=O(g^{19}\operatorname{poly}\log g)$. We introduce a number of new techniques, including a conceptually simple and almost entirely self-contained proof of the theorem that achieves a polynomial bound on $f(g)$.

Connected through hyperedge HE-1 (induced by source paper "theta triangle free and even hole k_4 free graphs part 1 layered wheels"):
  with members:
    - "structure and algorithms for cap even hole free graphs"
    - "on rank width of even hole free graphs"
    - "on the structure of pan even hole free graphs"
    - "the k in a path problem for claw free graphs"

Connected through hyperedge HE-2 (induced by source paper "large minors in expanders"):
  with members:
    - "towards tight er bounds for the excluded grid theorem"
    - "polynomial bounds for the grid minor theorem"
    - "routing in undirected graphs with constant congestion"
    - "a constructive proof of the general lovasz local lemma"

Connected through hyperedge HE-3 (induced by source paper "towards tight er bounds for the excluded grid theorem"):
  with members:
    - "degree 3 treewidth sparsifiers"
    - "polynomial bounds for the grid minor theorem"

Connected through hyperedge HE-4 (induced by source paper "extension complexity of the correlation polytope"):
  with members:
    - "extension complexity of independent set polytopes"
    - "communication complexity for algorithm designers"
    - "extended formulation for csp that is compact for instances of bounded treewidth"
    - "polynomial bounds for the grid minor theorem"

Connected through hyperedge HE-5 (induced by source paper "the half integral erdos posa property for non null cycles"):
  with members:
    - "half integrality lp branching and fpt algorithms"
    - "polynomial bounds for the grid minor theorem"
    - "on group feedback vertex set parameterized by the size of the cutset"
    - "finding small separators in linear time via treewidth reduction"

Connected through hyperedge HE-6 (induced by source paper "bidimensionality and kernels"):
  with members:
    - "linear kernels for edge deletion problems to immersion closed graph classes"
    - "neighborhood complexity and kernelization for nowhere dense classes of graphs"
    - "kernelization and sparseness the case of dominating set"
    - "explicit linear kernels via dynamic programming"
    - "bidimensionality of geometric intersection graphs"
    - "polynomial bounds for the grid minor theorem"
    - "kernels for connected dominating set on graphs with excluded topological subgraphs"
    - "linear kernels and single exponential algorithms via protrusion decompositions"

Connected through hyperedge HE-7 (induced by source paper "finding detours is fixed parameter tractable"):
  with members:
    - "mixing color coding related techniques"
    - "the directed grid theorem"
    - "polynomial bounds for the grid minor theorem"
    - "vertex cover problem parameterized above and below tight bounds"
    - "solving max r sat above a tight lower bound"

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)