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 greedy spanner is existentially optimal"
  Abstract: The greedy spanner is arguably the simplest and most well-studied spanner construction. Experimental results demonstrate that it is at least as good as any other spanner construction, in terms of both the size and weight parameters. However, a rigorous proof for this statement has remained elusive. #R##N#In this work we fill in the theoretical gap via a surprisingly simple observation: The greedy spanner is \emph{existentially optimal} (or existentially near-optimal) for several important graph families. Focusing on the weight parameter, the state-of-the-art spanner constructions for both general graphs (due to Chechik and Wulff-Nilsen [SODA'16]) and doubling metrics (due to Gottlieb [FOCS'15]) are complex. Plugging our observation on these results, we conclude that the greedy spanner achieves near-optimal weight guarantees for both general graphs and doubling metrics, thus resolving two longstanding conjectures in the area. #R##N#Further, we observe that approximate-greedy algorithms are existentially near-optimal as well. Consequently, we provide an $O(n \log n)$-time construction of $(1+\epsilon)$-spanners for doubling metrics with constant lightness and degree. Our construction improves Gottlieb's construction, whose runtime is $O(n \log^2 n)$ and whose number of edges and degree are unbounded, and remarkably, it matches the state-of-the-art Euclidean result (due to Gudmundsson et al. [SICOMP'02]) in all the involved parameters (up to dependencies on $\epsilon$ and the dimension).

Connected through hyperedge HE-1 (induced by source paper "a polynomial time algorithm for almost optimal vertex fault tolerant spanners"):
  with members:
    - "a trivial yet optimal solution to vertex fault tolerant spanners"
    - "optimal vertex fault tolerant spanners for fixed stretch"
    - "fault tolerant spanners better and simpler"

Connected through hyperedge HE-2 (induced by source paper "on the edge crossings of the greedy spanner"):
  with members:
    - "crossing patterns in nonplanar road networks"
    - "a light metric spanner"
    - "structured recursive separator decompositions for planar graphs in linear time"

Connected through hyperedge HE-3 (induced by source paper "graph spanners a tutorial review"):
  with members:
    - "near additive spanners and near exact hopsets a unified view"
    - "some general structure for extremal sparsification problems"
    - "weighted additive spanners"
    - "near additive spanners in low polynomial deterministic congest time"
    - "multi level graph sketches via single level solvers"
    - "almost shortest paths and pram distance oracles in weighted graphs"
    - "an fpt algorithm for minimum additive spanner problem"
    - "distributed construction of light networks"

Connected through hyperedge HE-4 (induced by source paper "distributed construction of light networks"):
  with members:
    - "light spanners for high dimensional norms via stochastic decompositions"
    - "greedy spanners are optimal in doubling metrics"
    - "distributed exact shortest paths in sublinear time"
    - "improved distributed algorithms for exact shortest paths"
    - "a simple deterministic distributed mst algorithm with near optimal time and message complexities"
    - "constructing light spanners deterministically in near linear time"
    - "minor free graphs have light spanners"
    - "near optimal approximate shortest paths and transshipment in distributed and streaming models"

Connected through hyperedge HE-5 (induced by source paper "truly optimal euclidean spanners"):
  with members:
    - "on the spanning and routing ratio of theta four"
    - "odd yao yao graphs are not spanners"
    - "greedy spanners are optimal in doubling metrics"
    - "minor free graphs have light spanners"
    - "almost all even yao yao graphs are spanners"
    - "a light metric spanner"
    - "upper bounds on the spanning ratio of constrained theta graphs"
    - "new and improved spanning ratios for yao graphs"

Connected through hyperedge HE-6 (induced by source paper "on strong diameter padded decompositions"):
  with members:
    - "light spanners for high dimensional norms via stochastic decompositions"
    - "ramsey spanning trees and their applications"
    - "efficient algorithms for constructing very sparse spanners and emulators"
    - "a linear size logarithmic stretch path reporting distance oracle for general graphs"
    - "a light metric spanner"
    - "metric decompositions of path separable graphs"
    - "space efficient path reporting approximate distance oracles"
    - "vertex sparsifiers new results from old techniques"

Connected through hyperedge HE-7 (induced by source paper "near linear time approximation schemes for steiner tree and forest in low dimensional spaces"):
  with members:
    - "greedy spanners are optimal in doubling metrics"
    - "a ptas for the steiner forest problem in doubling metrics"
    - "the traveling salesman problem low dimensionality implies a polynomial time approximation scheme"
    - "a light metric spanner"
    - "a polynomial time approximation scheme for euclidean steiner forest"
    - "an efficient polynomial time approximation scheme for steiner forest in planar graphs"
    - "approximation schemes for steiner forest on planar graphs and graphs of bounded treewidth"
    - "fast construction of nets in low dimensional metrics and their applications"

Connected through hyperedge HE-8 (induced by source paper "the norms of graph spanners"):
  with members:
    - "sherali adams integrality gaps matching the log density threshold"
    - "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"
    - "transitive closure 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)