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: "towards tight er bounds for the excluded grid theorem"
  Abstract: We study the Excluded Grid Theorem, a fundamental structural result in graph theory, that was proved by Robertson and Seymour in their seminal work on graph minors. The theorem states that there is a function $f: \mathbb{Z}^+ \to \mathbb{Z}^+$, such that for every integer $g>0$, every graph of treewidth at least $f(g)$ contains the $(g\times g)$-grid as a minor. For every integer $g>0$, let $f(g)$ be the smallest value for which the theorem holds. Establishing tight bounds on $f(g)$ is an important graph-theoretic question. Robertson and Seymour showed that $f(g)=\Omega(g^2\log g)$ must hold. For a long time, the best known upper bounds on $f(g)$ were super-exponential in $g$. The first polynomial upper bound of $f(g)=O(g^{98}\text{poly}\log g)$ was proved by Chekuri and Chuzhoy. It was later improved to $f(g) = O(g^{36}\text{poly} \log g)$, and then to $f(g)=O(g^{19}\text{poly}\log g)$. In this paper we further improve this bound to $f(g)=O(g^{9}\text{poly} \log g)$. We believe that our proof is significantly simpler than the proofs of the previous bounds. Moreover, while there are natural barriers that seem to prevent the previous methods from yielding tight bounds for the theorem, it seems conceivable that the techniques proposed in this paper can lead to even tighter bounds on $f(g)$.

Connected through hyperedge HE-1 (induced by source paper "the parameterized complexity of motion planning for snake like robots"):
  with members:
    - "coordinated motion planning reconfiguring a swarm of labeled robots with bounded stretch"
    - "push pull block puzzles are hard"
    - "how to navigate through obstacles"
    - "a survey of motion planning and control techniques for self driving urban vehicles"
    - "polynomial bounds for the grid minor theorem"
    - "kernelization lower bounds by cross composition"

Connected through hyperedge HE-2 (induced by source paper "towards a theory of parameterized streaming algorithms"):
  with members:
    - "the sparse awakens streaming algorithms for matching size estimation in sparse graphs"
    - "tight bounds for single pass streaming complexity of the set cover problem"
    - "towards tight bounds for the streaming set cover problem"
    - "polynomial bounds for the grid minor theorem"
    - "directed subset feedback vertex set is fixed parameter tractable"

Connected through hyperedge HE-3 (induced by source paper "large minors in expanders"):
  with members:
    - "improved 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-4 (induced by source paper "improved bounds for the excluded minor approximation of treedepth"):
  with members:
    - "a faster parameterized algorithm for treedepth"

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)