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: "finding large clique minors is hard"
  Abstract: We prove that it is NP-complete, given a graph G and a parameter h, to determine whether G contains a complete graph K_h as a minor.

Connected through hyperedge HE-1 (induced by source paper "contracting to a longest path in h free graphs"):
  with members:
    - "on the parameterized complexity of contraction to generalization of trees"
    - "independent feedback vertex set for p_5 free graphs"
    - "contracting bipartite graphs to paths and cycles"
    - "polynomial time algorithms for the longest induced path and induced disjoint paths problems on graphs of bounded mim width"
    - "a faster fpt algorithm for bipartite contraction"
    - "obtaining planarity by contracting few edges"
    - "finding small separators in linear time via treewidth reduction"
    - "contracting graphs to paths and trees"

Connected through hyperedge HE-2 (induced by source paper "hadwiger number of graphs with small chordality"):
  with members:
    - "contracting graphs to paths and trees"

Connected through hyperedge HE-3 (induced by source paper "the computational complexity of disconnected cut and 2k2 partition"):
  with members:
    - "contracting graphs to paths and trees"

Connected through hyperedge HE-4 (induced by source paper "paired approximation problems and incompatible inapproximabilities"):
  with members:
    - "approximate graph coloring by semidefinite programming"

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)