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: "hypergraphic lp relaxations for steiner trees"
  Abstract: We investigate hypergraphic LP relaxations for the Steiner tree problem, primarily the partition LP relaxation introduced by Konemann et al. [Math. Programming, 2009]. Specifically, we are interested in proving upper bounds on the integrality gap of this LP, and studying its relation to other linear relaxations. Our results are the following.#R##N##R##N#Structural results: We extend the technique of uncrossing, usually applied to families of sets, to families of partitions. As a consequence we show that any basic feasible solution to the partition LP formulation has sparse support. Although the number of variables could be exponential, the number of positive variables is at most the number of terminals.#R##N##R##N#Relations with other relaxations: We show the equivalence of the partition LP relaxation with other known hypergraphic relaxations. We also show that these hypergraphic relaxations are equivalent to the well studied bidirected cut relaxation, if the instance is quasibipartite.#R##N##R##N#Integrality gap upper bounds: We show an upper bound of $\sqrt{3} \doteq 1.729$ on the integrality gap of these hypergraph relaxations in general graphs. In the special case of uniformly quasibipartite instances, we show an improved upper bound of 73/60≐1.216. By our equivalence theorem, the latter result implies an improved upper bound for the bidirected cut relaxation as well.

Connected through hyperedge HE-1 (induced by source paper "simplex based steiner tree instances yield large integrality gaps for the bidirected cut relaxation"):
  with members:
    - "a partition based relaxation for steiner trees"

Connected through hyperedge HE-2 (induced by source paper "strong steiner tree approximations in practice"):
  with members:
    - "dijkstra meets steiner a fast exact goal oriented steiner tree algorithm"
    - "a robust and scalable algorithm for the steiner problem in graphs"
    - "approximation algorithms for steiner tree problems based on universal solution frameworks"
    - "speeding up dynamic programming with representative sets an experimental evaluation of algorithms for steiner tree on tree decompositions"
    - "a partition based relaxation for steiner trees"

Connected through hyperedge HE-3 (induced by source paper "approximating minimum cost connectivity orientation and augmentation"):
  with members:
    - "steiner forest orientation problems"

Connected through hyperedge HE-4 (induced by source paper "matroids and integrality gaps for hypergraphic steiner tree relaxations"):
  with members:
    - "a partition based relaxation for steiner trees"

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)