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: "kernel s for problems with no kernel on out trees with many leaves"
  Abstract: The {\sc $k$-Leaf Out-Branching} problem is to find an out-branching (i.e. a rooted oriented spanning tree) with at least $k$ leaves in a given digraph. The problem has recently received much attention from the viewpoint of parameterized algorithms {alonLNCS4596,AlonFGKS07fsttcs,BoDo2,KnLaRo}. In this paper we step aside and take a kernelization based approach to the {\sc $k$-Leaf-Out-Branching} problem. We give the first polynomial kernel for {\sc Rooted $k$-Leaf-Out-Branching}, a variant of {\sc $k$-Leaf-Out-Branching} where the root of the tree searched for is also a part of the input. Our kernel has cubic size and is obtained using extremal combinatorics. #R##N#For the {\sc $k$-Leaf-Out-Branching} problem we show that no polynomial kernel is possible unless polynomial hierarchy collapses to third level %$PH=\Sigma_p^3$ by applying a recent breakthrough result by Bodlaender et al. {BDFH08} in a non-trivial fashion. However our positive results for {\sc Rooted $k$-Leaf-Out-Branching} immediately imply that the seemingly intractable the {\sc $k$-Leaf-Out-Branching} problem admits a data reduction to $n$ independent $O(k^3)$ kernels. These two results, tractability and intractability side by side, are the first separating {\it many-to-one kernelization} from {\it Turing kernelization}. This answers affirmatively an open problem regarding "cheat kernelization" raised in {IWPECOPEN08}.

Connected through hyperedge HE-1 (induced by source paper "a polynomial turing kernel for weighted independent set in bull free graphs"):
  with members:
    - "turing kernelization for finding long paths and cycles in restricted graph classes"
    - "improved fpt algorithms for weighted independent set in bull free graphs"
    - "coloring perfect graphs with no balanced skew partitions"
    - "combinatorial optimization with 2 joins"
    - "maximum weight independent sets in odd hole free graphs without dart or without bull"
    - "on finding directed trees with many leaves"

Connected through hyperedge HE-2 (induced by source paper "kernelization of packing problems"):
  with members:
    - "bidimensionality and kernels"
    - "preprocessing for treewidth a combinatorial analysis through kernelization"
    - "cross composition a new technique for kernelization lower bounds"
    - "preprocessing of min ones problems a dichotomy"

Connected through hyperedge HE-3 (induced by source paper "confronting intractability via parameters"):
  with members:
    - "slightly superexponential parameterized problems"
    - "bidimensionality and kernels"
    - "how good is the chord algorithm"
    - "minimizing movement fixed parameter tractability"
    - "dynamic programming for graphs on surfaces"
    - "courcelle s theorem a game theoretic approach"
    - "preprocessing for treewidth a combinatorial analysis through kernelization"
    - "solving connectivity problems parameterized by treewidth in single exponential time"

Connected through hyperedge HE-4 (induced by source paper "constraint satisfaction problems parameterized above or below tight bounds a survey"):
  with members:
    - "simultaneously satisfying linear equations over mathbb f _2 maxlin2 and max r lin2 parameterized above average"
    - "hypercontractive inequality for pseudo boolean functions of bounded fourier width"
    - "a new bound for 3 satisfiable maxsat and its algorithmic application"
    - "parameterized complexity of maxsat above average"
    - "on multiway cut parameterized above lower bounds"
    - "improved parameterized algorithms for constraint satisfaction"
    - "a new lower bound on the maximum number of satisfied clauses in max sat and its algorithmic application"
    - "betweenness parameterized above tight lower bound"

Connected through hyperedge HE-5 (induced by source paper "limits of preprocessing"):
  with members:
    - "backdoors to tractable answer set programming"
    - "kernels for global constraints"
    - "range and roots two common patterns for specifying and propagating counting and occurrence constraints"
    - "the parameterized complexity of global constraints"
    - "cutset sampling for bayesian networks"
    - "stable models and an alternative logic programming paradigm"

Connected through hyperedge HE-6 (induced by source paper "co nondeterminism in compositions a kernelization lower bound for a ramsey type problem"):
  with members:
    - "kernelization of packing problems"
    - "cross composition a new technique for kernelization lower bounds"
    - "preprocessing of min ones problems a dichotomy"

Connected through hyperedge HE-7 (induced by source paper "beyond bidimensionality parameterized subexponential algorithms on directed graphs"):
  with members:
    - "efficient computation of representative sets with applications in parameterized and exact algorithms"
    - "subexponential parameterized algorithm for computing the cutwidth of a semi complete digraph"
    - "solving connectivity problems parameterized by treewidth in single exponential time"
    - "faster algorithms for feedback arc set tournament kemeny rank aggregation and betweenness tournament"
    - "on finding directed trees with many leaves"
    - "faster fast feedback arc set in tournaments"
    - "algorithm for finding k vertex out trees and its application to k internal out branching problem"
    - "a linear vertex kernel for maximum internal spanning tree"

Connected through hyperedge HE-8 (induced by source paper "note on maximal bisection above tight lower bound"):
  with members:
    - "vertex cover problem parameterized above and below tight bounds"
    - "betweenness parameterized above tight lower bound"
    - "a probabilistic approach to problems parameterized above or below tight bounds"
    - "solving max r sat above a tight lower bound"
    - "note on max lin 2 above average"
    - "fixed parameter complexity of minimum profile problems"
    - "the linear arrangement problem parameterized above guaranteed value"

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)