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: "greedy algorithms for steiner forest"
  Abstract: In the Steiner Forest problem, we are given terminal pairs $\{s_i, t_i\}$, and need to find the cheapest subgraph which connects each of the terminal pairs together. In 1991, Agrawal, Klein, and Ravi, and Goemans and Williamson gave primal-dual constant-factor approximation algorithms for this problem; until now, the only constant-factor approximations we know are via linear programming relaxations. #R##N#We consider the following greedy algorithm: Given terminal pairs in a metric space, call a terminal "active" if its distance to its partner is non-zero. Pick the two closest active terminals (say $s_i, t_j$), set the distance between them to zero, and buy a path connecting them. Recompute the metric, and repeat. Our main result is that this algorithm is a constant-factor approximation. #R##N#We also use this algorithm to give new, simpler constructions of cost-sharing schemes for Steiner forest. In particular, the first "group-strict" cost-shares for this problem implies a very simple combinatorial sampling-based algorithm for stochastic Steiner forest.

Connected through hyperedge HE-1 (induced by source paper "the power of recourse better algorithms for facility location in online and dynamic models"):
  with members:
    - "a tree structure for dynamic facility location"
    - "facility location problem in differential privacy model revisited"
    - "online facility location with deletions"
    - "online bipartite matching with amortized o log 2 n replacements"
    - "online and dynamic algorithms for set cover"
    - "efficient construction of probabilistic tree embeddings"
    - "facility location in evolving metrics"
    - "online network design algorithms via hierarchical decompositions"

Connected through hyperedge HE-2 (induced by source paper "on the complexity of local graph transformations"):
  with members:
    - "a local search algorithm for steiner forest"
    - "locality based network creation games"
    - "basic network creation games with communication interests"

Connected through hyperedge HE-3 (induced by source paper "efficient black box reductions for separable cost sharing"):
  with members:
    - "a characterization of undirected graphs admitting optimal cost shares"
    - "designing networks with good equilibria under uncertainty"
    - "resource buying games"
    - "strategic cooperation in cost sharing games"
    - "an o lognloglogn upper bound on the price of stability for undirected shapley network design games"
    - "approximation schemes for steiner forest on planar graphs and graphs of bounded treewidth"
    - "an optimal bifactor approximation algorithm for the metric uncapacitated facility location problem"

Connected through hyperedge HE-4 (induced by source paper "a ptas for the steiner forest problem in doubling metrics"):
  with members:
    - "the traveling salesman problem low dimensionality implies a polynomial time approximation scheme"
    - "a polynomial time approximation scheme for euclidean steiner forest"
    - "euclidean prize collecting steiner forest"
    - "approximation schemes for steiner forest on planar graphs and graphs of bounded treewidth"

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)