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: "approximation algorithm for minimum weight fault tolerant virtual backbone in unit disk graphs"
  Abstract: In a wireless sensor network, the virtual backbone plays an important role. Due to accidental damage or energy depletion, it is desirable that the virtual backbone is fault-tolerant. A fault-tolerant virtual backbone can be modeled as a    $k$   -connected    $m$   -fold dominating set (   $(k,m)$   -CDS for short). In this paper, we present a constant approximation algorithm for the minimum weight    $(k,m)$   -CDS problem in unit disk graphs under the assumption that    $k$    and    $m$    are two fixed constants with    $m\geq k$   . Prior to this paper, constant approximation algorithms are known for    $k=1$    with weight and    $2\leq k\leq 3$    without weight. Our result is the first constant approximation algorithm for the    $(k,m)$   -CDS problem with general    $k,m$    and with weight. The performance ratio is    $(\alpha +5\rho )$    for    $k\geq 3$    and    $(\alpha +2.5\rho )$    for    $k=2$   , where    $\alpha $    is the performance ratio for the minimum weight    $m$   -fold dominating set problem and    $\rho $    is the performance ratio for the subset    $k$   -connected subgraph problem (both problems are known to have constant performance ratios).

Connected through hyperedge HE-1 (induced by source paper "2 node connectivity network design"):
  with members:
    - "breaching the 2 approximation barrier for connectivity augmentation a reduction to steiner tree"
    - "approximating k connected m dominating sets"
    - "improved approximation for tree augmentation saving by rewiring"
    - "on the tree augmentation problem"
    - "a simplified 1 5 approximation algorithm for augmenting edge connectivity of a graph from 1 to 2"
    - "improved approximation algorithms for budgeted node weighted steiner problems"
    - "nearly tight low stretch spanning trees"
    - "lower stretch spanning trees"

Connected through hyperedge HE-2 (induced by source paper "an o log 2 n approximation algorithm for 2 edge connected dominating set"):
  with members:
    - "approximating k connected m dominating sets"
    - "analyzing the optimal neighborhood algorithms for budgeted and partial connected dominating set problems"
    - "nearly tight low stretch spanning trees"
    - "lower stretch spanning trees"

Connected through hyperedge HE-3 (induced by source paper "approximating k connected m dominating sets"):
  with members:
    - "improved approximation algorithms for k connected m dominating set problems"
    - "approximating source location and star survivable network problems"
    - "approximating subset k connectivity problems"

Connected through hyperedge HE-4 (induced by source paper "adaptive algorithm for finding connected dominating sets in uncertain graphs"):
  with members:
    - "approximation algorithms for optimal decision trees and adaptive tsp problems"
    - "the power of local information in social networks"

Connected through hyperedge HE-5 (induced by source paper "improved approximation algorithms for k connected m dominating set problems"):
  with members:
    - "constant approximation algorithms for highly connected multi dominating sets in unit disk graphs"
    - "spider covers for prize collecting network activation problem"
    - "parameters of two prover one round game and the hardness of connectivity problems"
    - "an improved approximation algorithm for the minimum cost subset k connected subgraph problem"
    - "approximating subset k connectivity problems"

Connected through hyperedge HE-6 (induced by source paper "fault tolerant virtual backbone in heterogeneous wireless sensor network"):
  with members:
    - "a sequential algorithm for generating random graphs"

Connected through hyperedge HE-7 (induced by source paper "a grasp approach for solving the 2 connected m dominating set problem"):
  with members:
    - "a heuristic approach for dividing graphs into bi connected components with a size constraint"

Connected through hyperedge HE-8 (induced by source paper "constant approximation algorithms for highly connected multi dominating sets in unit disk graphs"):
  with members:
    - "latency bounded target set selection in social networks"
    - "on the approximability and exact algorithms for vector domination and related problems in graphs"
    - "spider covers for prize collecting network activation problem"

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)