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: "flipping cubical meshes"
  Abstract: We define and examine flip operations for quadrilateral and hexahedral meshes, similar to the flipping transformations previously used in triangular and tetrahedral mesh generation.

Connected through hyperedge HE-1 (induced by source paper "finding hexahedrizations for small quadrangulations of the sphere"):
  with members:
    - "a 36 element solution to schneiders pyramid hex meshing problem and a parity changing template for hex mesh revision"
    - "a 44 element mesh of schneiders pyramid bounding the difficulty of hex meshing problems"
    - "identifying combinations of tetrahedra into hexahedra a vertex based strategy"
    - "gpu accelerated spectral finite elements on all hex meshes"
    - "subgraph isomorphism in planar graphs and related problems"
    - "linear complexity hexahedral mesh generation"

Connected through hyperedge HE-2 (induced by source paper "a 44 element mesh of schneiders pyramid bounding the difficulty of hex meshing problems"):
  with members:
    - "a 36 element solution to schneiders pyramid hex meshing problem and a parity changing template for hex mesh revision"
    - "robust and efficient validation of the linear hexahedral element"
    - "linear complexity hexahedral mesh generation"

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)