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: "the complexity landscape of fixed parameter directed steiner network problems"
  Abstract: Given a directed graph $G$ and a list $(s_1,t_1),\dots,(s_d,t_d)$ of terminal pairs, the Directed Steiner Network problem asks for a minimum-cost subgraph of $G$ that contains a directed $s_i\to t_i$ path for every $1\le i \le k$. The special case Directed Steiner Tree (when we ask for paths from a root $r$ to terminals $t_1,\dots,t_d$) is known to be fixed-parameter tractable parameterized by the number of terminals, while the special case Strongly Connected Steiner Subgraph (when we ask for a path from every $t_i$ to every other $t_j$) is known to be W[1]-hard. We systematically explore the complexity landscape of directed Steiner problems to fully understand which other special cases are FPT or W[1]-hard. Formally, if $\mathcal{H}$ is a class of directed graphs, then we look at the special case of Directed Steiner Network where the list $(s_1,t_1),\dots,(s_d,t_d)$ of requests form a directed graph that is a member of $\mathcal{H}$. Our main result is a complete characterization of the classes $\mathcal{H}$ resulting in fixed-parameter tractable special cases: we show that if every pattern in $\mathcal{H}$ has the combinatorial property of being "transitively equivalent to a bounded-length caterpillar with a bounded number of extra edges," then the problem is FPT, and it is W[1]-hard for every recursively enumerable $\mathcal{H}$ not having this property. This complete dichotomy unifies and generalizes the known results showing that Directed Steiner Tree is FPT [Dreyfus and Wagner, Networks 1971], $q$-Root Steiner Tree is FPT for constant $q$ [Such\'y, WG 2016], Strongly Connected Steiner Subgraph is W[1]-hard [Guo et al., SIAM J. Discrete Math. 2011], and Directed Steiner Network is solvable in polynomial-time for constant number of terminals [Feldman and Ruhl, SIAM J. Comput. 2006], and moreover reveals a large continent of tractable cases that were not known before.

Connected through hyperedge HE-1 (induced by source paper "a relaxation of the directed disjoint paths problem a global congestion metric helps"):
  with members:
    - "dual parameterization of weighted coloring"
    - "routing with congestion in acyclic digraphs"
    - "the directed grid theorem"
    - "network sparsification for steiner problems on planar and bounded genus graphs"
    - "the planar directed k vertex disjoint paths problem is fixed parameter tractable"
    - "fixed parameter tractability of multicut in directed acyclic graphs"
    - "parameterized complexity of directed steiner tree on sparse graphs"
    - "fixed parameter tractability of directed multiway cut parameterized by the size of the cutset"

Connected through hyperedge HE-2 (induced by source paper "complexity of the steiner network problem with respect to the number of terminals"):
  with members:
    - "on directed steiner trees with multiple roots"

Connected through hyperedge HE-3 (induced by source paper "parameterized approximation algorithms for directed steiner network problems"):
  with members:
    - "complexity of the steiner network problem with respect to the number of terminals"
    - "eth hardness of approximating 2 csps and directed steiner network"
    - "from gap eth to fpt inapproximability clique dominating set and more"
    - "on subexponential parameterized algorithms for steiner tree and directed subset tsp on planar graphs"
    - "parameterized complexity and approximability of directed odd cycle transversal"
    - "subexponential parameterized algorithms for planar and apex minor free graphs via low treewidth pattern covering"
    - "almost polynomial ratio eth hardness of approximating densest k subgraph"
    - "fixed parameter approximations for k center problems in low highway dimension graphs"

Connected through hyperedge HE-4 (induced by source paper "parameterized approximation schemes for steiner trees with small number of steiner vertices"):
  with members:
    - "the constant inapproximability of the parameterized dominating set problem"
    - "analytical approach to parallel repetition"
    - "fixed parameter and approximation algorithms a new look"

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)