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: "approximating graphic tsp by matchings"
  Abstract: We present a framework for approximating the metric TSP based on a novel use of matchings. Traditionally, matchings have been used to add edges in order to make a given graph Eulerian, whereas our approach also allows for the removal of certain edges leading to a decreased cost. #R##N#For the TSP on graphic metrics (graph-TSP), the approach yields a 1.461-approximation algorithm with respect to the Held-Karp lower bound. For graph-TSP restricted to a class of graphs that contains degree three bounded and claw-free graphs, we show that the integrality gap of the Held-Karp relaxation matches the conjectured ratio 4/3. The framework allows for generalizations in a natural way and also leads to a 1.586-approximation algorithm for the traveling salesman path problem on graphic metrics where the start and end vertices are prespecified.

Connected through hyperedge HE-1 (induced by source paper "simple cubic graphs with no short traveling salesman tour"):
  with members:
    - "graphic tsp in cubic graphs"
    - "cubic tsp a 1 3 approximation"
    - "tsp tours in cubic graphs beyond 4 3"
    - "the traveling salesman problem on cubic and subcubic graphs"

Connected through hyperedge HE-2 (induced by source paper "graphic tsp in cubic graphs"):
  with members:
    - "approximation hardness of graphic tsp on cubic graphs"
    - "new inapproximability bounds for tsp"
    - "improved inapproximability for tsp"
    - "the traveling salesman problem on cubic and subcubic graphs"
    - "13 9 approximation for graphic tsp"

Connected through hyperedge HE-3 (induced by source paper "reassembling trees for the traveling salesman"):
  with members:
    - "an experimental evaluation of the best of many christofides algorithm for the traveling salesman problem"
    - "better s t tours by gao trees"
    - "on the metric s t path traveling salesman problem"
    - "eight fifth approximation for the path tsp"
    - "approximating minimum cost connected t joins"
    - "improving christofides algorithm for the s t path tsp"
    - "13 9 approximation for graphic tsp"

Connected through hyperedge HE-4 (induced by source paper "an experimental evaluation of the best of many christofides algorithm for the traveling salesman problem"):
  with members:
    - "better s t tours by gao trees"
    - "reassembling trees for the traveling salesman"
    - "on the metric s t path traveling salesman problem"
    - "eight fifth approximation for the path tsp"
    - "improving christofides algorithm for the s t path tsp"
    - "13 9 approximation for graphic tsp"

Connected through hyperedge HE-5 (induced by source paper "approximating atsp by relaxing connectivity"):
  with members:
    - "effective resistance reducing flows spectrally thin trees and asymmetric tsp"
    - "the kadison singer problem for strongly rayleigh measures and applications to asymmetric tsp"
    - "new inapproximability bounds for tsp"
    - "13 9 approximation for graphic tsp"
    - "the asymmetric traveling salesman problem on graphs with bounded genus"

Connected through hyperedge HE-6 (induced by source paper "improved approximations for cubic and cubic bipartite tsp"):
  with members:
    - "cubic tsp a 1 3 approximation"
    - "a 9 7 approximation algorithm for graphic tsp in cubic bipartite graphs"
    - "tsp tours in cubic graphs beyond 4 3"
    - "13 9 approximation for graphic tsp"

Connected through hyperedge HE-7 (induced by source paper "constant factor approximation for atsp with two edge weights"):
  with members:
    - "approximating atsp by relaxing connectivity"
    - "new inapproximability bounds for tsp"
    - "13 9 approximation for graphic tsp"
    - "the asymmetric traveling salesman problem on graphs with bounded genus"

Connected through hyperedge HE-8 (induced by source paper "graph tsp from steiner cycles"):
  with members:
    - "eight fifth approximation for the path tsp"
    - "shorter tours by nicer ears 7 5 approximation for graphic tsp 3 2 for the path version and 4 3 for two edge connected subgraphs"
    - "a 4 3 approximation for tsp on cubic 3 edge connected graphs"
    - "13 9 approximation for graphic tsp"

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)