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: "a ptas for subset tsp in minor free graphs"
  Abstract: We give the first polynomial time approximation scheme for the subset Traveling Salesperson Problem (subset TSP) in $H$-minor-free graphs. Our main technical contribution is a polynomial time algorithm that, given an edge-weighted $H$-minor-free graph $G$ and a set of $k$ terminals $T$, finds a subgraph of $G$ with weight at most $O_H(\mathrm{poly}(\frac{1}{\epsilon}) \log k)$ times the weight of the minimum Steiner tree for $T$ that preserves pairwise distances between terminals up to $(1+\epsilon)$ factor. This is the first such spanner for $H$-minor-free graphs. Given this spanner, we use the contraction decomposition of Demaine, Hajiaghayi and Kawarabayashi to obtain a PTAS for the subset TSP problem. Our PTAS generalizes PTASes for the same problem by Klein for planar graphs and by Borradaile, Demaine and Tazari for bounded genus 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)