human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge is induced by one source paper and its member nodes are the cited papers.

Details of the hypergraph:
Center hyperedge (induced by source paper "the snow team problem clearing directed subgraphs by mobile agents"):
  Abstract: We study several problems of clearing subgraphs by mobile agents in digraphs. The agents can move only along directed walks of a digraph and, depending on the variant, their initial positions may be pre-specified. In general, for a given subset~$\mathcal{S}$ of vertices of a digraph $D$ and a positive integer $k$, the objective is to determine whether there is a subgraph $H=(\mathcal{V}_H,\mathcal{A}_H)$ of $D$ such that (a) $\mathcal{S} \subseteq \mathcal{V}_H$, (b) $H$ is the union of $k$ directed walks in $D$, and (c) the underlying graph of $H$ includes a Steiner tree for $\mathcal{S}$ in $D$. We provide several results on the polynomial time tractability, hardness, and parameterized complexity of the problem.

Includes members:
  Member "on directed steiner trees with multiple roots":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "complexity of the steiner network problem with respect to the number of terminals")
  Member "approximating directed steiner problems via tree embedding":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "polylogarithmic approximation algorithm for k connected directed steiner tree on quasi bipartite graphs")
  Member "covering pairs in directed acyclic graphs":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "an external memory algorithm for string graph construction")
  Member "an algorithmic metatheorem for directed treewidth":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "parametrised algorithms for directed modular width")
  Member "from pathwidth to connected pathwidth":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "finding small width connected path decompositions in polynomial time")
  Member "parameterized complexity of directed steiner tree on sparse graphs":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "tight bounds for planar strongly connected steiner subgraph with fixed number of terminals and extensions")
  Member "connected searching of weighted trees":
    also connected through other hyperedges:
      - Hyperedge HE-7 (induced by source paper "finding small width connected path decompositions in polynomial time")
  Member "complexity of the path avoiding forbidden pairs problem revisited":
    also connected through other hyperedges:
      (none)

Question: Please tell me which class the source paper 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)