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: "3 coloring in time o 1 3289 n"
  Abstract: We consider worst case time bounds for NP-complete problems including 3-SAT, 3-coloring, 3-edge-coloring, and 3-list-coloring. Our algorithms are based on a constraint satisfaction (CSP) formulation of these problems. 3-SAT is equivalent to (2,3)-CSP while the other problems above are special cases of (3,2)-CSP; there is also a natural duality transformation from (a,b)-CSP to (b,a)-CSP. We give a fast algorithm for (3,2)-CSP and use it to improve the time bounds for solving the other problems listed above. Our techniques involve a mixture of Davis-Putnam-style backtracking with more sophisticated matching and network flow based ideas.

Connected through hyperedge HE-1 (induced by source paper "exponential time quantum algorithms for graph coloring problems"):
  with members:
    - "on problems as hard as cnf sat"
    - "faster graph coloring in polynomial space"

Connected through hyperedge HE-2 (induced by source paper "tight lower bounds on graph embedding problems"):
  with members:
    - "everything you always wanted to know about the parameterized complexity of subgraph isomorphism but were afraid to ask"
    - "determinant sums for undirected hamiltonicity"
    - "bandwidth and distortion revisited"

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

Connected through hyperedge HE-4 (induced by source paper "on the dynamic width of the 3 colorability problem"):
  with members:
    - "lower bounds for existential pebble games and k consistency tests"
    - "on the speed of constraint propagation and the time complexity of arc consistency testing"
    - "planar graphs logical complexity and parallel isomorphism tests"

Connected through hyperedge HE-5 (induced by source paper "on the subexponential time complexity of csp"):
  with members:
    - "tractable hypergraph properties for constraint satisfaction and conjunctive queries"
    - "hypertree decompositions and tractable queries"

Connected through hyperedge HE-6 (induced by source paper "algorithms and almost tight results for 3 colorability of small diameter graphs"):
  with members:
    - "the complexity of surjective homomorphism problems a survey"

Connected through hyperedge HE-7 (induced by source paper "determining l 2 1 span in polynomial space"):
  with members:
    - "channel assignment via fast zeta transform"
    - "small maximal independent sets and faster exact graph coloring"

Connected through hyperedge HE-8 (induced by source paper "a universally fastest algorithm for max 2 sat max 2 csp and everything in between"):
  with members:
    - "feedback vertex set in mixed graphs"
    - "a new upper bound for max 2 sat a graph theoretic approach"

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.DS(Data Structures and Algorithms)