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: "a note on planar partial 3 trees"
  Abstract: It implicitly follows from the work of [Colbourn, El-Mallah: On two dual classes of planar graphs. Discrete Mathematics 80(1): 21-40 (1990)] that every planar partial 3-tree is a subgraph of a planar 3-tree. This fact has already enabled to prove a couple of results for planar partial 3-trees by induction on the structure of the underlying planar 3-tree completion. We provide an explicit proof of this observation and strengthen it by showing that one can keep the plane drawing of the input graph unchanged.

Connected through hyperedge HE-1 (induced by source paper "planar graphs have bounded queue number"):
  with members:
    - "shorter labeling schemes for planar graphs"
    - "planar graphs of bounded degree have constant queue number"
    - "polynomial bounds for centered colorings on proper minor closed graph classes"
    - "queue layouts of planar 3 trees"
    - "layouts for plane graphs on constant number of tracks"
    - "an annotated bibliography on 1 planarity"
    - "stack and queue layouts via layered separators"
    - "on the queue number of graphs with bounded tree width"

Connected through hyperedge HE-2 (induced by source paper "drawing planar graphs with many collinear vertices"):
  with members:
    - "the utility of untangling"
    - "untangling planar graphs from a specified vertex position hard cases"
    - "untangling polygons and graphs"
    - "untangling a planar graph"
    - "a polynomial bound for untangling geometric planar graphs"
    - "on collinear sets in straight line drawings"

Connected through hyperedge HE-3 (induced by source paper "sefe with no mapping via large induced outerplane graphs in plane graphs"):
  with members:
    - "simultaneous embedding 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.DM(Discrete Mathematics)