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: "sorting by transpositions is difficult"
  Abstract: In comparative genomics, a transposition is an operation that exchanges two consecutive sequences of genes in a genome. The transposition distance between two genomes, that is, the minimum number of transpositions needed to transform a genome into another, is, according to numerous studies, a relevant evolutionary distance. The problem of computing this distance when genomes are represented by permutations is called the Sorting by Transpositions problem, and has been introduced by Bafna and Pevzner in [Proceedings of the Sixth Annual ACM-SIAM Symposium on Discrete Algorithms, 1995, pp. 614--623]. It has naturally been the focus of a number of studies (see, for instance, [G. Fertin, A. Labarre, I. Rusu, E. Tannier, and S. Vialette, Combinatorics of Genome Rearrangements, The MIT Press, Cambridge, MA, 2009]), but the computational complexity of this problem has remained undetermined for 15 years. In this paper, we answer this long-standing open question by proving that the Sorting by Transpositions problem ...

Connected through hyperedge HE-1 (induced by source paper "an algebraic 1 375 approximation algorithm for the transposition distance problem"):
  with members:
    - "log lists and their applications to sorting by transpositions reversals and block interchanges"

Connected through hyperedge HE-2 (induced by source paper "block crossings in storyline visualizations"):
  with members:
    - "on minimizing crossings in storyline visualizations"

Connected through hyperedge HE-3 (induced by source paper "rearrangement problems with duplicated genomic markers"):
  with members:
    - "on sampling scj rearrangement scenarios"
    - "pancake flipping is hard"
    - "polynomial time sortable stacks of burnt pancakes"
    - "genome halving by block interchange"
    - "on the complexity of rearrangement problems under the breakpoint distance"
    - "the zero exemplar distance problem"

Connected through hyperedge HE-4 (induced by source paper "ordering metro lines by block crossings"):
  with members:
    - "drawing permutations with few corners"
    - "exact and fixed parameter algorithms for metro line crossing minimization problems"
    - "metro line crossing minimization hardness approximations and tractable cases"

Connected through hyperedge HE-5 (induced by source paper "the distribution of cycles in breakpoint graphs of signed permutations"):
  with members:
    - "pancake flipping is hard"
    - "polynomial time sortable stacks of burnt pancakes"

Connected through hyperedge HE-6 (induced by source paper "lower bounding edit distances between permutations"):
  with members:
    - "pancake flipping is hard"

Connected through hyperedge HE-7 (induced by source paper "sorting of permutations by cost constrained transpositions"):
  with members:
    - "codes in permutations and error correction for rank modulation"

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)