human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge is induced by one source paper and its member nodes are the cited papers.

Details of the hypergraph:
Center hyperedge (induced by source paper "the graphs of planar soap bubbles"):
  Abstract: We characterize the graphs formed by two-dimensional soap bubbles as being exactly the 3-regular bridgeless planar multigraphs. Our characterization combines a local characterization of soap bubble graphs in terms of the curvatures of arcs meeting at common vertices, a proof that this characterization remains invariant under Moebius transformations, an application of Moebius invariance to prove bridgelessness, and a Moebius-invariant power diagram of circles previously developed by the author for its applications in graph drawing.

Includes members:
  Member "steinitz theorems for simple orthogonal polyhedra":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "realization and connectivity of the graphs of origami flat foldings")
  Member "drawing trees with perfect angular resolution and polynomial area":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "bipartite and series parallel graphs without planar lombardi drawings")
  Member "planar lombardi drawings for subcubic graphs":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "on smooth orthogonal and octilinear drawings relations complexity and kandinsky drawings")
  Member "small grid embeddings of 3 polytopes":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "embedding stacked polytopes on a polynomial size grid")
  Member "lombardi drawings of graphs":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "bipartite and series parallel graphs without planar lombardi drawings")
  Member "steiner trees and spanning trees in six pin soap films":
    also connected through other hyperedges:
      (none)
  Member "moebius invariant natural neighbor interpolation":
    also connected through other hyperedges:
      (none)
  Member "optimal moebius transformations for information visualization and meshing":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "the galois complexity of graph drawing why numerical solutions are ubiquitous for force directed spectral and circle packing drawings")

Question: Please tell me which class the source paper 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.DM(Discrete Mathematics)