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: "parameterized complexity of directed steiner tree on sparse graphs"
  Abstract: We study the parameterized complexity of the directed variant of the classical {\sc Steiner Tree} problem on various classes of directed sparse graphs. While the parameterized complexity of {\sc Steiner Tree} parameterized by the number of terminals is well understood, not much is known about the parameterization by the number of non-terminals in the solution tree. All that is known for this parameterization is that both the directed and the undirected versions are W[2]-hard on general graphs, and hence unlikely to be fixed parameter tractable FPT. The undirected {\sc Steiner Tree} problem becomes FPT when restricted to sparse classes of graphs such as planar graphs, but the techniques used to show this result break down on directed planar graphs. #R##N#In this article we precisely chart the tractability border for {\sc Directed Steiner Tree} (DST) on sparse graphs parameterized by the number of non-terminals in the solution tree. Specifically, we show that the problem is fixed parameter tractable on graphs excluding a topological minor, but becomes W[2]-hard on graphs of degeneracy 2. On the other hand we show that if the subgraph induced by the terminals is required to be acyclic then the problem becomes FPT on graphs of bounded degeneracy. #R##N#We further show that our algorithm achieves the best possible running time dependence on the solution size and degeneracy of the input graph, under standard complexity theoretic assumptions. Using the ideas developed for DST, we also obtain improved algorithms for {\sc Dominating Set} on sparse undirected graphs. These algorithms are asymptotically optimal.

Connected through hyperedge HE-1 (induced by source paper "tight bounds for planar strongly connected steiner subgraph with fixed number of terminals and extensions"):
  with members:
    - "fpt inapproximability of directed cut and connectivity problems"
    - "complexity of the steiner network problem with respect to the number of terminals"
    - "the parameterized complexity of finding point sets with hereditary properties"
    - "homomorphisms are a good basis for counting small subgraphs"
    - "parameterized approximation algorithms for directed steiner network problems"
    - "the graph motif problem parameterized by the structure of the input graph"
    - "on subexponential parameterized algorithms for steiner tree and directed subset tsp on planar graphs"
    - "on the parameterized complexity of red blue points separation"

Connected through hyperedge HE-2 (induced by source paper "a relaxation of the directed disjoint paths problem a global congestion metric helps"):
  with members:
    - "dual parameterization of weighted coloring"
    - "the complexity landscape of fixed parameter directed steiner network problems"
    - "routing with congestion in acyclic digraphs"
    - "the directed grid theorem"
    - "network sparsification for steiner problems on planar and bounded genus graphs"
    - "the planar directed k vertex disjoint paths problem is fixed parameter tractable"
    - "fixed parameter tractability of multicut in directed acyclic graphs"
    - "fixed parameter tractability of directed multiway cut parameterized by the size of the cutset"

Connected through hyperedge HE-3 (induced by source paper "greedy domination on biclique free graphs"):
  with members:
    - "approximation algorithms for polynomial expansion and low density graphs"
    - "analytical approach to parallel repetition"

Connected through hyperedge HE-4 (induced by source paper "the snow team problem clearing directed subgraphs by mobile agents"):
  with members:
    - "on directed steiner trees with multiple roots"
    - "approximating directed steiner problems via tree embedding"
    - "covering pairs in directed acyclic graphs"
    - "an algorithmic metatheorem for directed treewidth"
    - "from pathwidth to connected pathwidth"
    - "connected searching of weighted trees"
    - "complexity of the path avoiding forbidden pairs problem revisited"
    - "narrow sieves for parameterized paths and packings"

Connected through hyperedge HE-5 (induced by source paper "algorithmic properties of sparse digraphs"):
  with members:
    - "characterising bounded expansion by neighbourhood complexity"
    - "polynomial kernels and wideness properties of nowhere dense graph classes"
    - "bidimensionality and kernels"
    - "neighborhood complexity and kernelization for nowhere dense classes of graphs"
    - "kernelization and sparseness the case of dominating set"
    - "kernelization using structural parameters on sparse graph classes"

Connected through hyperedge HE-6 (induced by source paper "on directed steiner trees with multiple roots"):
  with members:
    - "fixed parameter and approximation algorithms a new look"
    - "fpt algorithms for connected feedback vertex set"

Connected through hyperedge HE-7 (induced by source paper "everything you always wanted to know about the parameterized complexity of subgraph isomorphism but were afraid to ask"):
  with members:
    - "on feedback vertex set new measure and new structures"
    - "kernels for connected dominating set on graphs with excluded topological subgraphs"
    - "linear kernels on graphs excluding topological minors"
    - "structure theorem and isomorphism test for graphs with excluded topological subgraphs"
    - "finding topological subgraphs is fixed parameter tractable"
    - "deciding first order properties of locally tree decomposable structures"

Connected through hyperedge HE-8 (induced by source paper "kernels for connected dominating set on graphs with excluded topological subgraphs"):
  with members:
    - "tight kernel bounds for problems on graphs with small degeneracy"
    - "linear kernels and single exponential algorithms via protrusion decompositions"
    - "structure theorem and isomorphism test for graphs with excluded topological subgraphs"
    - "bidimensionality and geometric graphs"
    - "hitting forbidden minors approximation and kernelization"
    - "bidimensionality and eptas"
    - "beyond bidimensionality parameterized subexponential algorithms on directed graphs"
    - "solving dominating set in larger classes of graphs fpt algorithms and polynomial kernels"

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)