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: "flip distance between triangulations of a planar point set is apx hard"
  Abstract: In this work we consider triangulations of point sets in the Euclidean plane, i.e., maximal straight-line crossing-free graphs on a finite set of points. Given a triangulation of a point set, an edge flip is the operation of removing one edge and adding another one, such that the resulting graph is again a triangulation. Flips are a major way of locally transforming triangular meshes. We show that, given a point set S in the Euclidean plane and two triangulations T"1 and T"2 of S, it is an APX-hard problem to minimize the number of edge flips to transform T"1 to T"2.

Connected through hyperedge HE-1 (induced by source paper "shortest reconfiguration of perfect matchings via alternating cycles"):
  with members:
    - "the perfect matching reconfiguration problem"
    - "shortest reconfiguration of matchings"
    - "the time complexity of permutation routing via matching token swapping and a variant"
    - "flip distance between triangulations of a simple polygon is np complete"
    - "shortest reconfiguration of sliding tokens on a caterpillar"
    - "finding shortest paths between graph colourings"
    - "shortest reconfiguration paths in the solution space of boolean formulas"
    - "the complexity of change"

Connected through hyperedge HE-2 (induced by source paper "an improved fpt algorithm for the flip distance problem"):
  with members:
    - "flip distance between triangulations of a simple polygon is np complete"
    - "computing the flip distance between triangulations"

Connected through hyperedge HE-3 (induced by source paper "minimum weight connectivity augmentation for planar straight line graphs"):
  with members:
    - "on the relationship between k planar and k quasi planar graphs"
    - "an annotated bibliography on 1 planarity"
    - "crossing patterns in nonplanar road networks"
    - "two planar graphs are quasiplanar"
    - "on the density of non simple 3 planar graphs"
    - "recognizing and drawing ic planar graphs"
    - "a simplified 1 5 approximation algorithm for augmenting edge connectivity of a graph from 1 to 2"
    - "on the recognition of fan planar and maximal outer fan planar graphs"

Connected through hyperedge HE-4 (induced by source paper "shortest reconfiguration of matchings"):
  with members:
    - "an improved fpt algorithm for the flip distance problem"
    - "solving the rubik s cube optimally is np complete"
    - "the complexity of independent set reconfiguration on bipartite graphs"
    - "a reconfigurations analogue of brooks theorem and its consequences"
    - "flip distance between triangulations of a simple polygon is np complete"
    - "shortest reconfiguration of sliding tokens on a caterpillar"
    - "recoloring graphs via tree decompositions"
    - "shortest reconfiguration paths in the solution space of boolean formulas"

Connected through hyperedge HE-5 (induced by source paper "a note on the flip distance problem for edge labeled triangulations"):
  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"

Connected through hyperedge HE-6 (induced by source paper "a proof of the orbit conjecture for flipping edge labelled triangulations"):
  with members:
    - "reconfiguring ordered bases of a matroid"
    - "flips in edge labelled pseudo triangulations"
    - "flip distance between triangulations of a simple polygon is np complete"
    - "computing the flip distance between triangulations"
    - "the complexity of change"
    - "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-7 (induced by source paper "minimum weight connectivity augmentation for planar straight line graphs"):
  with members:
    - "minimum weight connectivity augmentation for planar straight line graphs"
    - "a simplified 1 5 approximation algorithm for augmenting edge connectivity of a graph from 1 to 2"
    - "fixed parameter algorithms for minimum cost edge connectivity augmentation"
    - "approximating the edge length of 2 edge connected planar geometric graphs on a set of points"
    - "computing homotopic shortest paths efficiently"

Connected through hyperedge HE-8 (induced by source paper "arc diagrams flip distances and hamiltonian triangulations"):
  with members:
    - "a lower bound on the diameter of the flip graph"
    - "making triangulations 4 connected using flips"
    - "a history of flips in combinatorial triangulations"

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.CG(Computational Geometry)