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: "improved approximation for node disjoint paths in planar graphs"
  Abstract: We study the classical Node-Disjoint Paths (NDP) problem: given an $n$-vertex graph $G$ and a collection $M=\{(s_1,t_1),\ldots,(s_k,t_k)\}$ of pairs of vertices of $G$ called demand pairs, find a maximum-cardinality set of node-disjoint paths connecting the demand pairs. NDP is one of the most basic routing problems, that has been studied extensively. Despite this, there are still wide gaps in our understanding of its approximability: the best currently known upper bound of $O(\sqrt n)$ on its approximation ratio is achieved via a simple greedy algorithm, while the best current negative result shows that the problem does not have a better than $\Omega(\log^{1/2-\delta}n)$-approximation for any constant $\delta$, under standard complexity assumptions. Even for planar graphs no better approximation algorithms are known, and to the best of our knowledge, the best negative bound is APX-hardness. Perhaps the biggest obstacle to obtaining better approximation algorithms for NDP is that most currently known approximation algorithms for this type of problems rely on the standard multicommodity flow relaxation, whose integrality gap is $\Omega(\sqrt n)$ for NDP, even in planar graphs. In this paper, we break the barrier of $O(\sqrt n)$ on the approximability of the NDP problem in planar graphs and obtain an $\tilde O(n^{9/19})$-approximation. We introduce a new linear programming relaxation of the problem, and a number of new techniques, that we hope will be helpful in designing more powerful algorithms for this and related problems.

Connected through hyperedge HE-1 (induced by source paper "an approximation algorithm for fully planar edge disjoint paths"):
  with members:
    - "almost polynomial hardness of node disjoint paths in grids"
    - "new hardness results for routing on disjoint paths"
    - "routing in undirected graphs with constant congestion"

Connected through hyperedge HE-2 (induced by source paper "shortest k disjoint paths via determinants"):
  with members:
    - "towards single face shortest vertex disjoint paths in undirected planar graphs"
    - "planarity testing revisited"

Connected through hyperedge HE-3 (induced by source paper "improved approximation for node disjoint paths in grids with sources on the boundary"):
  with members:
    - "new algorithms for maximum disjoint paths based on tree likeness"
    - "routing in undirected graphs with constant congestion"

Connected through hyperedge HE-4 (induced by source paper "almost polynomial hardness of node disjoint paths in grids"):
  with members:
    - "improved approximation for node disjoint paths in grids with sources on the boundary"
    - "almost polynomial ratio eth hardness of approximating densest k subgraph"
    - "new algorithms for maximum disjoint paths based on tree likeness"
    - "new hardness results for routing on disjoint paths"
    - "routing in undirected graphs with constant congestion"

Connected through hyperedge HE-5 (induced by source paper "routing symmetric demands in directed minor free graphs with constant congestion"):
  with members:
    - "a polylogarithimic approximation algorithm for edge disjoint paths with congestion 2"

Connected through hyperedge HE-6 (induced by source paper "new algorithms for maximum disjoint paths based on tree likeness"):
  with members:
    - "new hardness results for routing on disjoint paths"
    - "on routing disjoint paths in bounded treewidth graphs"
    - "maximum edge disjoint paths in k sums of graphs"
    - "a polylogarithimic approximation algorithm for edge disjoint paths with congestion 2"
    - "routing in undirected graphs with constant congestion"
    - "flow cut gaps for integer and fractional multiflows"

Connected through hyperedge HE-7 (induced by source paper "new hardness results for routing on disjoint paths"):
  with members:
    - "a polylogarithimic approximation algorithm for edge disjoint paths with congestion 2"
    - "routing in undirected graphs with constant congestion"

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)