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: "list coloring apex minor free graphs"
  Abstract: A graph H is t-apex if H-X is planar for some set X\subset V(H) of size t. For any integer t>=0 and a fixed t-apex graph H, we give a polynomial-time algorithm to decide whether a (t+3)-connected H-minor-free graph is colorable from a given assignment of lists of size t+4. The connectivity requirement is the best possible in the sense that for every t>=1, there exists a t-apex graph H such that testing (t+4)-colorability of (t+2)-connected H-minor-free graphs is NP-complete. Similarly, the size of the lists cannot be decreased (unless P=NP), since for every t>=1, testing (t+3)-list-colorability of (t+3)-connected K_{t+4}-minor-free graphs is NP-complete.

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 "filling the complexity gaps for colouring planar and bounded degree graphs"):
  with members:
    - "partitioning a triangle free planar graph into a forest and a forest of bounded degree"
    - "a survey on the computational complexity of colouring graphs with forbidden subgraphs"
    - "list coloring embedded graphs"
    - "the complexity of planar graph choosability"

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)