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: "time approximation trade offs for inapproximable problems"
  Abstract: In this paper we focus on problems which do not admit a constant-factor approximation in polynomial time and explore how quickly their approximability improves as the allowed running time is gradually increased from polynomial to (sub-)exponential. #R##N#We tackle a number of problems: For Min Independent Dominating Set, Max Induced Path, Forest and Tree, for any $r(n)$, a simple, known scheme gives an approximation ratio of $r$ in time roughly $r^{n/r}$. We show that, for most values of $r$, if this running time could be significantly improved the ETH would fail. For Max Minimal Vertex Cover we give a non-trivial $\sqrt{r}$-approximation in time $2^{n/r}$. We match this with a similarly tight result. We also give a $\log r$-approximation for Min ATSP in time $2^{n/r}$ and an $r$-approximation for Max Grundy Coloring in time $r^{n/r}$. #R##N#Furthermore, we show that Min Set Cover exhibits a curious behavior in this super-polynomial setting: for any $\delta > 0$ it admits an $m^\delta$-approximation, where $m$ is the number of sets, in just quasi-polynomial time. We observe that if such ratios could be achieved in polynomial time, the ETH or the Projection Games Conjecture would fail.

Connected through hyperedge HE-1 (induced by source paper "improved in approximability bounds for d scattered set"):
  with members:
    - "kernelization and approximation of distance r independent sets on nowhere dense graphs"
    - "structurally parameterized d scattered set"
    - "on distance d independent set and other problems in graphs with few minimal separators"
    - "optimal parameterized algorithms for planar facility location problems using voronoi diagrams"
    - "independent set induced matching and pricing connections and tight subexponential time approximation hardnesses"
    - "bidimensionality and eptas"
    - "exponential time approximation of hard problems"

Connected through hyperedge HE-2 (induced by source paper "from gap eth to fpt inapproximability clique dominating set and more"):
  with members:
    - "completely inapproximable monotone and antimonotone parameterized problems"
    - "almost polynomial ratio eth hardness of approximating densest k subgraph"
    - "a birthday repetition theorem and complexity of approximating dense csps"
    - "how to refute a random csp"
    - "eth hardness for densest k subgraph with perfect completeness"
    - "the constant inapproximability of the parameterized dominating set problem"
    - "lower bounds on the size of semidefinite programming relaxations"
    - "the parameterized complexity of k biclique"

Connected through hyperedge HE-3 (induced by source paper "new tools and connections for exponential time approximation"):
  with members:
    - "from gap eth to fpt inapproximability clique dominating set and more"
    - "a birthday repetition theorem and complexity of approximating dense csps"
    - "sparsification and subexponential approximation"
    - "independent set induced matching and pricing connections and tight subexponential time approximation hardnesses"
    - "exponential time approximation of hard problems"

Connected through hyperedge HE-4 (induced by source paper "lower bounds for the parameterized complexity of minimum fill in and other completion problems"):
  with members:
    - "on the threshold of intractability"
    - "a polynomial kernel for trivially perfect editing"
    - "a subexponential parameterized algorithm for proper interval completion"
    - "a subexponential parameterized algorithm for interval completion"
    - "sparsification and subexponential approximation"
    - "exploring subexponential parameterized complexity of completion problems"
    - "parameterized in approximability of subset problems"
    - "subexponential parameterized algorithm for minimum fill in"

Connected through hyperedge HE-5 (induced by source paper "complexity of grundy coloring and its variants"):
  with members:
    - "known algorithms for edge clique cover are probably optimal"
    - "known algorithms on graphs of bounded treewidth are probably optimal"
    - "fixed parameter tractability definability and model checking"

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)