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: "rotation distance is fixed parameter tractable"
  Abstract: Rotation distance between trees measures the number of simple operations it takes to transform one tree into another. There are no known polynomial-time algorithms for computing rotation distance. In the case of ordered rooted trees, we show that the rotation distance between two ordered trees is fixed-parameter tractable, in the parameter, k, the rotation distance. The proof relies on the kernalization of the initial trees to trees with size bounded by 7k.

Connected through hyperedge HE-1 (induced by source paper "reconfiguration on sparse graphs"):
  with members:
    - "reconfiguration on nowhere dense graph classes"
    - "token jumping in minor closed classes"
    - "polynomial kernels and wideness properties of nowhere dense graph classes"
    - "faster online matrix vector multiplication"
    - "vertex cover reconfiguration and beyond"
    - "reconfiguration over tree decompositions"
    - "finding shortest paths between graph colourings"
    - "reconfiguration in bounded bandwidth and treedepth"

Connected through hyperedge HE-2 (induced by source paper "computing the flip distance between triangulations"):
  with members:
    - "flip distance between triangulations of a simple polygon is np complete"
    - "vertex cover reconfiguration and beyond"
    - "flip distance between triangulations of a planar point set is apx hard"
    - "reconfiguration over tree decompositions"
    - "on the parameterized complexity of reconfiguration problems"
    - "flip distance between two triangulations of a point set is np complete"

Connected through hyperedge HE-3 (induced by source paper "flip distance between triangulations of a planar point set is apx hard"):
  with members:
    - "flip distance between triangulations of a simple polygon is np complete"
    - "flipping edge labelled triangulations"
    - "flip distance between two triangulations of a point set is np complete"
    - "happy endings for flip graphs"

Connected through hyperedge HE-4 (induced by source paper "flip distance between two triangulations of a point set is np complete"):
  with members:
    - "flip distance between triangulations of a simple polygon is np complete"
    - "flip distance between triangulations of a planar point set is apx hard"
    - "making triangulations 4 connected using flips"
    - "happy endings for flip graphs"

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)