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: "spanning directed trees with many leaves"
  Abstract: The {\sc Directed Maximum Leaf Out-Branching} problem is to find an out-branching (i.e. a rooted oriented spanning tree) in a given digraph with the maximum number of leaves. In this paper, we obtain two combinatorial results on the number of leaves in out-branchings. We show that #R##N#- every strongly connected $n$-vertex digraph $D$ with minimum in-degree at least 3 has an out-branching with at least $(n/4)^{1/3}-1$ leaves; #R##N#- if a strongly connected digraph $D$ does not contain an out-branching with $k$ leaves, then the pathwidth of its underlying graph UG($D$) is $O(k\log k)$. Moreover, if the digraph is acyclic, the pathwidth is at most $4k$. #R##N#The last result implies that it can be decided in time $2^{O(k\log^2 k)}\cdot n^{O(1)}$ whether a strongly connected digraph on $n$ vertices has an out-branching with at least $k$ leaves. On acyclic digraphs the running time of our algorithm is $2^{O(k\log k)}\cdot n^{O(1)}$.

Connected through hyperedge HE-1 (induced by source paper "on balanced clustering with tree like structures over clusters"):
  with members:
    - "structured connectivity augmentation"
    - "approximate hierarchical clustering via sparsest cut and spreading metrics"
    - "a cost function for similarity based hierarchical clustering"

Connected through hyperedge HE-2 (induced by source paper "k distinct in and out branchings in digraphs"):
  with members:
    - "the directed grid theorem"

Connected through hyperedge HE-3 (induced by source paper "towards detection of bottlenecks in modular systems"):
  with members:
    - "multiset estimates and combinatorial synthesis"
    - "improvement extension of modular systems as combinatorial reengineering survey"
    - "morphological methods for design of modular systems a survey"

Connected through hyperedge HE-4 (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-5 (induced by source paper "on finding directed trees with many leaves"):
  with members:
    - "kernel s for problems with no kernel on out trees with many leaves"
    - "parameterized algorithms for directed maximum leaf problems"
    - "an fpt algorithm for directed spanning k leaf"

Connected through hyperedge HE-6 (induced by source paper "fpt algorithms and kernels for the directed k leaf problem"):
  with members:
    - "parameterized algorithms for directed maximum leaf problems"
    - "an fpt algorithm for directed spanning k leaf"
    - "better algorithms and bounds for directed maximum leaf problems"

Connected through hyperedge HE-7 (induced by source paper "on complexity of minimum leaf out branching problem"):
  with members:
    - "digraph decompositions and monotonicity in digraph searching"

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)