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: "approximability of sparse integer programs"
  Abstract: The main focus of this paper is a pair of new approximation algorithms for certain integer programs. First, for covering integer programs {min cx: Ax >= b, 0  = 2 and eps>0, if P != NP this ratio cannot be improved to k-1-eps, and under the unique games conjecture this ratio cannot be improved to k-eps. One key idea is to replace individual constraints by others that have better rounding properties but the same nonnegative integral solutions; another critical ingredient is knapsack-cover inequalities. Second, for packing integer programs {max cx: Ax <= b, 0 <= x <= d} where A has at most k nonzeroes per column, we give a (2k^2+2)-approximation algorithm. Our approach builds on the iterated LP relaxation framework. In addition, we obtain improved approximations for the second problem when k=2, and for both problems when every A_{ij} is small compared to b_i. Finally, we demonstrate a 17/16-inapproximability for covering integer programs with at most two nonzeroes per column.

Connected through hyperedge HE-1 (induced by source paper "ell_1 sparsity approximation bounds for packing integer programs"):
  with members:
    - "on approximating sparse covering integer programs"
    - "partial resampling to approximate covering integer programs"
    - "submodular function maximization via the multilinear relaxation and contention resolution schemes"

Connected through hyperedge HE-2 (induced by source paper "algorithms to approximate column sparse packing problems"):
  with members:
    - "attenuate locally win globally an attenuation based framework for online stochastic matching with timeouts"
    - "random order contention resolution schemes"
    - "adaptivity gaps for stochastic probing submodular and xos functions"
    - "improved algorithmic bounds for discrepancy of sparse set systems"
    - "deterministic discrepancy minimization via the multiplicative weight update method"
    - "constrained submodular maximization via a non symmetric technique"
    - "constrained submodular maximization beyond 1 e"
    - "non negative submodular stochastic probing via stochastic contention resolution schemes"

Connected through hyperedge HE-3 (induced by source paper "a primal dual approximation algorithm for min sum single machine scheduling problems"):
  with members:
    - "how unsplittable flow covering helps scheduling with job dependent cost functions"
    - "dual techniques for scheduling on a machine with varying speed"
    - "the geometry of scheduling"
    - "scheduling with outliers"

Connected through hyperedge HE-4 (induced by source paper "approximating sparse covering integer programs online"):
  with members:
    - "on column restricted and priority covering integer programs"
    - "on k column sparse packing programs"
    - "approximation algorithms for covering packing integer programs"
    - "the k server dual and loose competitiveness for paging"

Connected through hyperedge HE-5 (induced by source paper "iterative packing for demand and hypergraph matching"):
  with members:
    - "on k column sparse packing programs"

Connected through hyperedge HE-6 (induced by source paper "an lp with integrality gap 1 epsilon for multidimensional knapsack"):
  with members:
    - "on column restricted and priority covering integer programs"
    - "approximability of capacitated network design"
    - "integrality gaps of linear and semi definite programming relaxations for knapsack"
    - "dependent randomized rounding for matroid polytopes and applications"

Connected through hyperedge HE-7 (induced by source paper "k edge connectivity approximation and lp relaxation"):
  with members:
    - "on k column sparse packing programs"

Connected through hyperedge HE-8 (induced by source paper "dependent randomized rounding for matroid polytopes and applications"):
  with members:
    - "symmetry and approximability of submodular maximization problems"
    - "approximating spanning trees with low crossing number"
    - "combinatorial auctions with decreasing marginal utilities"

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)