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: "bi factor approximation algorithms for hard capacitated k median problems"
  Abstract: The $k$-Facility Location problem is a generalization of the classical problems $k$-Median and Facility Location. The goal is to select a subset of at most $k$ facilities that minimizes the total cost of opened facilities and established connections between clients and opened facilities. We consider the hard-capacitated version of the problem, where a single facility may only serve a limited number of clients and creating multiple copies of a facility is not allowed. We construct approximation algorithms slightly violating the capacities based on rounding a fractional solution to the standard LP. #R##N#It is well known that the standard LP (even in the case of uniform capacities and opening costs) has unbounded integrality gap if we only allow violating capacities by a factor smaller than $2$, or if we only allow violating the number of facilities by a factor smaller than $2$. In this paper, we present the first constant-factor approximation algorithms for the hard-capacitated variants of the problem. For uniform capacities, we obtain a $(2+\varepsilon)$-capacity violating algorithm with approximation ratio $O(1/\varepsilon^2)$; our result has not yet been improved. Then, for non-uniform capacities, we consider the case of $k$-Median, which is equivalent to $k$-Facility Location with uniform opening cost of the facilities. Here, we obtain a $(3+\varepsilon)$-capacity violating algorithm with approximation ratio $O(1/\varepsilon)$.

Connected through hyperedge HE-1 (induced by source paper "reconciliation k median clustering with non polarized representatives"):
  with members:
    - "constant factor approximation for ordered k median"
    - "minimizing polarization and disagreement in social networks"
    - "balancing information exposure in social networks"
    - "joint non negative matrix factorization for learning ideological leaning on twitter"
    - "reducing controversy by connecting opposing views"
    - "better guarantees for k means and euclidean k median by primal dual algorithms"
    - "an improved approximation for k median and positive correlation in budgeted optimization"
    - "approximating k median via pseudo approximation"

Connected through hyperedge HE-2 (induced by source paper "improved local search based approximation algorithm for hard uniform capacitated k median problem"):
  with members:
    - "constant approximation for capacitated k median with 1 epsilon capacity violation"
    - "constant factor approximation algorithms for uniform hard capacitated facility location problems natural lp is not too bad"
    - "an approximation algorithm for uniform capacitated k median problem with 1 epsilon capacity violation"
    - "an improved approximation algorithm for the hard uniform capacitated k median problem"
    - "on uniform capacitated k median beyond the natural lp relaxation"
    - "approximation algorithms for capacitated facility location problem with penalties"
    - "approximation algorithms for hard capacitated k facility location problems"

Connected through hyperedge HE-3 (induced by source paper "constant factor approximation algorithms for uniform hard capacitated facility location problems natural lp is not too bad"):
  with members:
    - "constant approximation for capacitated k median with 1 epsilon capacity violation"
    - "an approximation algorithm for uniform capacitated k median problem with 1 epsilon capacity violation"
    - "an improved approximation algorithm for the hard uniform capacitated k median problem"
    - "on uniform capacitated k median beyond the natural lp relaxation"
    - "an improved approximation for k median and positive correlation in budgeted optimization"
    - "lp based algorithms for capacitated facility location"
    - "approximation algorithms for hard capacitated k facility location problems"
    - "improved approximation algorithms for matroid and knapsack median problems and applications"

Connected through hyperedge HE-4 (induced by source paper "constant approximation for capacitated k median with 1 epsilon capacity violation"):
  with members:
    - "an approximation algorithm for uniform capacitated k median problem with 1 epsilon capacity violation"
    - "an improved approximation algorithm for the hard uniform capacitated k median problem"
    - "on uniform capacitated k median beyond the natural lp relaxation"
    - "an improved approximation for k median and positive correlation in budgeted optimization"
    - "lp based algorithms for capacitated facility location"
    - "approximation algorithms for hard capacitated k facility location problems"
    - "approximating k median via pseudo approximation"

Connected through hyperedge HE-5 (induced by source paper "an approximation algorithm for uniform capacitated k median problem with 1 epsilon capacity violation"):
  with members:
    - "on uniform capacitated k median beyond the natural lp relaxation"
    - "an improved approximation for k median and positive correlation in budgeted optimization"
    - "lp based algorithms for capacitated facility location"
    - "approximating capacitated k median with 1 epsilon k open facilities"
    - "approximation algorithms for hard capacitated k facility location problems"
    - "approximating k median via pseudo approximation"

Connected through hyperedge HE-6 (induced by source paper "data driven resource allocation for distributed learning"):
  with members:
    - "an improved approximation algorithm for the hard uniform capacitated k median problem"
    - "improved distributed principal component analysis"
    - "decompositions of triangle dense graphs"
    - "approximation algorithms for hard capacitated k facility location problems"
    - "greedy facility location algorithms analyzed using dual fitting with factor revealing lp"

Connected through hyperedge HE-7 (induced by source paper "on uniform capacitated k median beyond the natural lp relaxation"):
  with members:
    - "an improved approximation algorithm for the hard uniform capacitated k median problem"
    - "an improved approximation for k median and positive correlation in budgeted optimization"
    - "lp based algorithms for capacitated facility location"
    - "approximating capacitated k median with 1 epsilon k open facilities"
    - "approximation algorithms for hard capacitated k facility location problems"
    - "approximating k median via pseudo approximation"
    - "an optimal bifactor approximation algorithm for the metric uncapacitated facility location problem"
    - "greedy facility location algorithms analyzed using dual fitting with factor revealing lp"

Connected through hyperedge HE-8 (induced by source paper "approximating capacitated k median with 1 epsilon k open facilities"):
  with members:
    - "an improved approximation algorithm for the hard uniform capacitated k median problem"
    - "on uniform capacitated k median beyond the natural lp relaxation"
    - "an improved approximation for k median and positive correlation in budgeted optimization"
    - "an improved approximation algorithm for k median problem using a new factor revealing lp"
    - "approximation algorithms for hard capacitated k facility location problems"
    - "approximating k median via pseudo approximation"
    - "an optimal bifactor approximation algorithm for the metric uncapacitated facility location problem"
    - "greedy facility location algorithms analyzed using dual fitting with factor revealing lp"

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)