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: "combinatorial coloring of 3 colorable graphs"
  Abstract: We consider the problem of coloring a 3-colorable graph in polynomial time using as few colors as possible. We present a combinatorial algorithm getting down to $\tO(n^{4/11})$ colors. This is the first combinatorial improvement of Blum's $\tO(n^{3/8})$ bound from FOCS'90. Like Blum's algorithm, our new algorithm composes nicely with recent semi-definite approaches. The current best bound is $O(n^{0.2072})$ colors by Chlamtac from FOCS'07. We now bring it down to $O(n^{0.2038})$ colors.

Connected through hyperedge HE-1 (induced by source paper "approximation algorithms for partially colorable graphs"):
  with members:
    - "a new algorithm for the robust semi random independent set problem"
    - "does robustness imply tractability a lower bound for planted clique in the semi random model"
    - "on the effect of randomness on planted 3 coloring models"
    - "faster parameterized algorithms using linear programming"
    - "rounding semidefinite programming hierarchies via global correlation"
    - "approximate graph coloring by semidefinite programming"

Connected through hyperedge HE-2 (induced by source paper "graph colouring algorithms"):
  with members:
    - "improved hardness of approximating chromatic number"
    - "computing the tutte polynomial in vertex exponential time"
    - "3 coloring in time o 1 3289 n"
    - "approximate graph coloring by semidefinite programming"

Connected through hyperedge HE-3 (induced by source paper "on the robust hardness of gr obner basis computation"):
  with members:
    - "exploiting chordal structure in polynomial ideals a grobner bases approach"
    - "conditional hardness for approximate coloring"
    - "approximate graph coloring by semidefinite programming"

Connected through hyperedge HE-4 (induced by source paper "hardness of finding independent sets in 2 colorable and almost 2 colorable hypergraphs"):
  with members:
    - "cuts in cartesian products of graphs"
    - "nearly optimal np hardness of vertex cover on k uniform k partite hypergraphs"
    - "conditional hardness for approximate coloring"
    - "a new multilayered pcp and the hardness of hypergraph vertex cover"
    - "approximate graph coloring by semidefinite programming"

Connected through hyperedge HE-5 (induced by source paper "hardness of finding independent sets in 2 colorable hypergraphs and of satisfiable csps"):
  with members:
    - "super polylogarithmic hypergraph coloring hardness via low degree long codes"
    - "conditional hardness for approximate coloring"
    - "approximate graph coloring by semidefinite programming"

Connected through hyperedge HE-6 (induced by source paper "improved hardness of approximating chromatic number"):
  with members:
    - "conditional hardness for approximate coloring"
    - "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)