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: "an improved approximation algorithm for the minimum cost subset k connected subgraph problem"
  Abstract: The minimum-cost subset $k$-connected subgraph problem is a cornerstone problem in the area of network design with vertex connectivity requirements. In this problem, we are given a graph $G=(V,E)$ with costs on edges and a set of terminals $T$. The goal is to find a minimum cost subgraph such that every pair of terminals are connected by $k$ openly (vertex) disjoint paths. In this paper, we present an approximation algorithm for the subset $k$-connected subgraph problem which improves on the previous best approximation guarantee of $O(k^2\log{k})$ by Nutov (FOCS 2009). Our approximation guarantee, $\alpha(|T|)$, depends upon the number of terminals: [\alpha(|T|) \ \ =\ \ O(|T|^2) & if |T| < 2k O(k \log^2 k) & if 2k\le |T| < k^2 O(k \log k) & if |T| \ge k^2] #R##N#So, when the number of terminals is {\em large enough}, the approximation guarantee improves significantly. Moreover, we show that, given an approximation algorithm for $|T|=k$, we can obtain almost the same approximation guarantee for any instances with $|T|> k$. This suggests that the hardest instances of the problem are when $|T|\approx k$.

Connected through hyperedge HE-1 (induced by source paper "polylogarithmic approximation algorithm for k connected directed steiner tree on quasi bipartite graphs"):
  with members:
    - "a quasi polynomial algorithm for submodular tree orienteering in directed graphs"
    - "a logarithmic integrality gap bound for directed steiner tree in quasi bipartite graphs"
    - "approximating directed steiner problems via tree embedding"
    - "analytical approach to parallel repetition"
    - "parameters of two prover one round game and the hardness of connectivity problems"
    - "approximating subset k connectivity problems"
    - "directed steiner tree and the lasserre hierarchy"
    - "an o k 3 log n approximation algorithm for vertex connectivity survivable network design"

Connected through hyperedge HE-2 (induced by source paper "node weighted network design in planar and minor closed families of graphs"):
  with members:
    - "improved approximation algorithms for budgeted node weighted steiner problems"
    - "spider covers for prize collecting network activation problem"
    - "approximation schemes for steiner forest on planar graphs and graphs of bounded treewidth"
    - "an o k 3 log n approximation algorithm for vertex connectivity survivable network design"

Connected through hyperedge HE-3 (induced by source paper "survivable network design for group connectivity in low treewidth graphs"):
  with members:
    - "a polynomial time approximation scheme for euclidean steiner forest"
    - "sparsest cut on bounded treewidth graphs algorithms and hardness results"
    - "parameters of two prover one round game and the hardness of connectivity problems"
    - "solving connectivity problems parameterized by treewidth in single exponential time"
    - "polynomial time approximation schemes for subset connectivity problems in bounded genus graphs"
    - "approximation schemes for steiner forest on planar graphs and graphs of bounded treewidth"
    - "an o k 3 log n approximation algorithm for vertex connectivity survivable network design"

Connected through hyperedge HE-4 (induced by source paper "improved approximation algorithms for k connected m dominating set problems"):
  with members:
    - "approximation algorithm for minimum weight fault tolerant virtual backbone in unit disk graphs"
    - "constant approximation algorithms for highly connected multi dominating sets in unit disk graphs"
    - "spider covers for prize collecting network activation problem"
    - "parameters of two prover one round game and the hardness of connectivity problems"
    - "approximating subset k connectivity problems"

Connected through hyperedge HE-5 (induced by source paper "surviving in directed graphs a polylogarithmic approximation for two connected directed steiner tree"):
  with members:
    - "parameters of two prover one round game and the hardness of connectivity problems"
    - "iterative rounding approximation algorithms for degree bounded node connectivity network design"
    - "approximating minimum cost k node connected subgraphs via independence free graphs"
    - "approximating subset k connectivity problems"
    - "directed steiner tree and the lasserre hierarchy"

Connected through hyperedge HE-6 (induced by source paper "parameters of two prover one round game and the hardness of connectivity problems"):
  with members:
    - "label cover instances with large girth and the hardness of approximating basic k spanner"
    - "approximation algorithms and hardness of the k route cut problem"
    - "a graph reduction step preserving element connectivity and applications"
    - "an o k 3 log n approximation algorithm for vertex connectivity survivable network design"

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)