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 graph reduction step preserving element connectivity and applications"
  Abstract: Given an undirected graph G=(V,E) and subset of terminals T \subseteq V, the element-connectivity of two terminals u,v \in T is the maximum number of u-v paths that are pairwise disjoint in both edges and non-terminals V \setminus T (the paths need not be disjoint in terminals). Element-connectivity is more general than edge-connectivity and less general than vertex-connectivity. Hind and Oellermann gave a graph reduction step that preserves the global element-connectivity of the graph. We show that this step also preserves local connectivity, that is, all the pairwise element-connectivities of the terminals. We give two applications of this reduction step to connectivity and network design problems: #R##N#1. Given a graph G and disjoint terminal sets T_1, T_2, ..., T_m, we seek a maximum number of element-disjoint Steiner forests where each forest connects each T_i. We prove that if each T_i is k-element-connected then there exist \Omega(\frac{k}{\log h \log m}) element-disjoint Steiner forests, where h = |\bigcup_i T_i|. If G is planar (or more generally, has fixed genus), we show that there exist \Omega(k) Steiner forests. Our proofs are constructive, giving poly-time algorithms to find these forests; these are the first non-trivial algorithms for packing element-disjoint Steiner Forests. #R##N#2. We give a very short and intuitive proof of a spider-decomposition theorem of Chuzhoy and Khanna in the context of the single-sink k-vertex-connectivity problem; this yields a simple and alternative analysis of an O(k \log n) approximation. #R##N#Our results highlight the effectiveness of the element-connectivity reduction step; we believe it will find more applications in the future.

Connected through hyperedge HE-1 (induced by source paper "characterizations of the connected forcing number of a graph"):
  with members:
    - "logic circuits from zero forcing"
    - "zero forcing number constrained matchings and strong structural controllability"

Connected through hyperedge HE-2 (induced by source paper "degree 3 treewidth sparsifiers"):
  with members:
    - "vertex sparsifiers new results from old techniques"
    - "flows in one crossing minor free graphs"
    - "polynomial bounds for the grid minor theorem"
    - "on sparsification for computing treewidth"
    - "a polylogarithimic approximation algorithm for edge disjoint paths with congestion 2"
    - "on vertex sparsifiers with steiner nodes"
    - "mimicking networks and succinct representations of terminal cuts"
    - "representative sets and irrelevant vertices new tools for kernelization"

Connected through hyperedge HE-3 (induced by source paper "polynomial bounds for the grid minor theorem"):
  with members:
    - "degree 3 treewidth sparsifiers"
    - "maximum edge disjoint paths in k sums of graphs"
    - "large treewidth graph decompositions and applications"
    - "a polylogarithimic approximation algorithm for edge disjoint paths with congestion 2"
    - "routing in undirected graphs with constant congestion"
    - "on brambles grid like minors and parameterized intractability of monadic second order logic"

Connected through hyperedge HE-4 (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"
    - "an improved approximation algorithm for the minimum cost subset k connected subgraph problem"
    - "approximation algorithms and hardness of the k route cut problem"
    - "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)