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: "untangling polygons and graphs"
  Abstract: Untangling is a process in which some vertices in a drawing of a planar graph are moved to obtain a straight-line plane drawing. The aim is to move as few vertices as possible. We present an algorithm that untangles the cycle graph C n while keeping Ω(n 2/3) vertices fixed.#R##N##R##N#For any connected graph G, we also present an upper bound on the number of fixed vertices in the worst case. The bound is a function of the number of vertices, maximum degree, and diameter of G. One consequence is that every 3-connected planar graph has a drawing δ such that at most O((nlog n)2/3) vertices are fixed in every untangling of δ.

Connected through hyperedge HE-1 (induced by source paper "drawing planar graphs with many collinear vertices"):
  with members:
    - "the utility of untangling"
    - "a note on planar partial 3 trees"
    - "untangling planar graphs from a specified vertex position hard cases"
    - "untangling a planar graph"
    - "a polynomial bound for untangling geometric planar graphs"
    - "on collinear sets in straight line drawings"

Connected through hyperedge HE-2 (induced by source paper "the utility of untangling"):
  with members:
    - "superpatterns and universal point sets"
    - "sefe with no mapping via large induced outerplane graphs in plane graphs"
    - "how many vertex locations can be arbitrarily chosen when drawing planar graphs"
    - "on universal point sets for planar graphs"
    - "simultaneous embedding of planar graphs"
    - "untangling planar graphs from a specified vertex position hard cases"
    - "on a tree and a path with no geometric simultaneous embedding"
    - "untangling a planar graph"

Connected through hyperedge HE-3 (induced by source paper "drawing arrangement graphs in small grids or how to play planarity"):
  with members:
    - "superpatterns and universal point sets"
    - "universal point sets for planar three tree"
    - "untangling a planar graph"
    - "a polynomial bound for untangling geometric planar graphs"
    - "on the obfuscation complexity of planar graphs"
    - "algorithms for drawing media"

Connected through hyperedge HE-4 (induced by source paper "untangling planar graphs from a specified vertex position hard cases"):
  with members:
    - "untangling a planar graph"
    - "a polynomial bound for untangling geometric planar graphs"
    - "on collinear sets in straight line drawings"
    - "on the obfuscation complexity of planar graphs"
    - "moving vertices to make drawings plane"

Connected through hyperedge HE-5 (induced by source paper "untangling a planar graph"):
  with members:
    - "a polynomial bound for untangling geometric planar graphs"
    - "on the obfuscation complexity of planar graphs"
    - "moving vertices to make drawings plane"
    - "the problem of compatible representatives"

Connected through hyperedge HE-6 (induced by source paper "a polynomial bound for untangling geometric planar graphs"):
  with members:
    - "on collinear sets in straight line drawings"
    - "on the obfuscation complexity of planar graphs"
    - "moving vertices to make drawings plane"

Connected through hyperedge HE-7 (induced by source paper "on collinear sets in straight line drawings"):
  with members:
    - "untangling planar graphs from a specified vertex position hard cases"
    - "untangling a planar graph"
    - "a polynomial bound for untangling geometric planar graphs"
    - "on the obfuscation complexity of planar 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.CG(Computational Geometry)