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: "transitive closure spanners"
  Abstract: Given a directed graph G = (V,E) and an integer k>=1, a k-transitive-closure-spanner (k-TC-spanner) of G is a directed graph H = (V, E_H) that has (1) the same transitive-closure as G and (2) diameter at most k. These spanners were implicitly studied in access control, data structures, and property testing, and properties of these spanners have been rediscovered over the span of 20 years. The main goal in each of these applications is to obtain the sparsest k-TC-spanners. We bring these diverse areas under the unifying framework of TC-spanners. #R##N#We initiate the study of approximability of the size of the sparsest k-TC-spanner for a given directed graph. We completely resolve the approximability of 2-TC-spanners, showing that it is Theta(log n) unless P = NP. For k>2, we present a polynomial-time algorithm that finds a k-TC-spanner with size within O((n log n)^{1-1/k}) of the optimum. Our algorithmic techniques also yield algorithms with the best-known approximation ratio for well-studied problems on directed spanners when k>3: DIRECTED k-SPANNER, CLIENT/SERVER DIRECTED k-SPANNER, and k-DIAMETER SPANNING SUBGRAPH. For constant k>=3, we show that the size of the sparsest k-TC-spanner is hard to approximate with 2^{log^{1-eps} n} ratio unless NP \subseteq DTIME(n^{polylog n}}). Finally, we study the size of the sparsest k-TC-spanners for H-minor-free graph families. Combining our constructions with our insight that 2-TC-spanners can be used for designing property testers, we obtain a monotonicity tester with O(log^2 n /eps) queries for any poset whose transitive reduction is an H-minor free digraph, improving the Theta(sqrt(n) log n/eps)-queries required of the tester due to Fischer et al (2002).

Connected through hyperedge HE-1 (induced by source paper "efficient and simple algorithms for fault tolerant spanners"):
  with members:
    - "a trivial yet optimal solution to vertex fault tolerant spanners"
    - "optimal vertex fault tolerant spanners for fixed stretch"
    - "parallel graph decompositions using random shifts"
    - "improved parallel algorithms for spanners and hopsets"
    - "fault tolerant spanners better and simpler"
    - "graph sparsification by effective resistances"
    - "randomized approximation schemes for cuts and flows in capacitated graphs"

Connected through hyperedge HE-2 (induced by source paper "approximating the distance to monotonicity of boolean functions"):
  with members:
    - "testing unateness nearly optimally"
    - "junta correlation is testable"
    - "lower bounds for tolerant junta and unateness testing via rejection sampling of graphs"
    - "beyond talagrand functions new lower bounds for testing monotonicity and unateness"
    - "settling the query complexity of non adaptive junta testing"
    - "optimal unateness testers for real valued functions adaptivity helps"
    - "tolerant junta testing and the connection to submodular optimization and function isomorphism"
    - "boolean function monotonicity testing requires almost n 1 2 non adaptive queries"

Connected through hyperedge HE-3 (induced by source paper "lasserre integrality gaps for graph spanners and related problems"):
  with members:
    - "characterizing demand graphs for fixed parameter shallow light steiner network"
    - "approximating spanners and directed steiner forest upper and lower bounds"
    - "parallel metric tree embedding based on an algebraic view on moore bellman ford"
    - "everywhere sparse spanners via dense subgraphs"
    - "label cover instances with large girth and the hardness of approximating basic k spanner"
    - "rounding semidefinite programming hierarchies via global correlation"
    - "fault tolerant spanners better and simpler"
    - "directed steiner tree and the lasserre hierarchy"

Connected through hyperedge HE-4 (induced by source paper "the norms of graph spanners"):
  with members:
    - "sherali adams integrality gaps matching the log density threshold"
    - "the greedy spanner is existentially optimal"
    - "minimizing the union tight approximations for small set bipartite vertex expansion"
    - "label cover instances with large girth and the hardness of approximating basic k spanner"
    - "fault tolerant spanners better and simpler"
    - "directed spanners via flow based linear programs"

Connected through hyperedge HE-5 (induced by source paper "approximation algorithms and an integer program for multi level graph spanners"):
  with members:
    - "multi level steiner trees"
    - "linear size distance preservers"
    - "on pairwise spanners"
    - "directed spanners via flow based linear programs"

Connected through hyperedge HE-6 (induced by source paper "finding options that minimize planning time"):
  with members:
    - "diversity is all you need learning skills without a reward function"
    - "when waiting is not an option learning options with a deliberation cost"
    - "a laplacian framework for option discovery in reinforcement learning"
    - "constructing abstraction hierarchies using a skill symbol loop"
    - "on the complexity of solving markov decision problems"
    - "analytical approach to parallel repetition"
    - "the complexity of plan existence and evaluation in probabilistic domains"
    - "label cover instances with large girth and the hardness of approximating basic k spanner"

Connected through hyperedge HE-7 (induced by source paper "exact distance oracles using hopsets"):
  with members:
    - "linear size hopsets with small hopbound and distributed routing with low memory"
    - "fast and compact exact distance oracle for planar graphs"
    - "beyond highway dimension small distance labels using tree skeletons"
    - "a hierarchy of lower bounds for sublinear additive spanners"
    - "hopsets with constant hopbound and applications to approximate shortest paths"
    - "sublinear space distance labeling using hubs"

Connected through hyperedge HE-8 (induced by source paper "congested clique algorithms for graph spanners"):
  with members:
    - "distributed symmetry breaking algorithms for congested cliques"
    - "brief announcement semi mapreduce meets congested clique"
    - "improved deterministic distributed construction of spanners"

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)