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 kernels for tracking path problems"
  Abstract: Given a graph $G$, terminal vertices $s$ and $t$, and an integer $k$, the Tracking Paths problem asks whether there exists at most $k$ vertices, which if marked as trackers, would ensure that the sequence of trackers encountered in each s-t path is unique. The problem was first proposed by Banik et al. in \cite{DBLP:conf/ciac/BanikKPS17}, where they gave results for some restricted versions of the problem. The problem was further studied in \cite{banik2019}, where the authors proved it to be NP-complete and fixed-parameter tractable. They obtained a kernel (i.e. an equivalent instance) with $O(k^6)$ vertices and $O(k^7)$ edges, in polynomial time. We improve on this by giving a quadratic kernel, i.e. $O(k^2)$ vertices and edges. Further, we prove that if $G$ is a $d$-degenerate graph then there exists a linear kernel. We also show that finding a tracking set of size at most $n-k$ for a graph on $n$ vertices is hard for the parameterized complexity class W[1], when parameterized by $k$.

Connected through hyperedge HE-1 (induced by source paper "polynomial time algorithms for tracking path problems"):
  with members:
    - "fixed parameter tractable algorithms for tracking shortest paths"
    - "tracking paths in planar graphs"

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)