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: "on pairwise spanners"
  Abstract: Given an undirected $n$-node unweighted graph $G = (V, E)$, a spanner with stretch function $f(\cdot)$ is a subgraph $H\subseteq G$ such that, if two nodes are at distance $d$ in $G$, then they are at distance at most $f(d)$ in $H$. Spanners are very well studied in the literature. The typical goal is to construct the sparsest possible spanner for a given stretch function. #R##N#In this paper we study pairwise spanners, where we require to approximate the $u$-$v$ distance only for pairs $(u,v)$ in a given set $\cP \subseteq V\times V$. Such $\cP$-spanners were studied before [Coppersmith,Elkin'05] only in the special case that $f(\cdot)$ is the identity function, i.e. distances between relevant pairs must be preserved exactly (a.k.a. pairwise preservers). #R##N#Here we present pairwise spanners which are at the same time sparser than the best known preservers (on the same $\cP$) and of the best known spanners (with the same $f(\cdot)$). In more detail, for arbitrary $\cP$, we show that there exists a $\mathcal{P}$-spanner of size $O(n(|\cP|\log n)^{1/4})$ with $f(d)=d+4\log n$. Alternatively, for any $\eps>0$, there exists a $\cP$-spanner of size $O(n|\cP|^{1/4}\sqrt{\frac{\log n}{\eps}})$ with $f(d)=(1+\eps)d+4$. We also consider the relevant special case that there is a critical set of nodes $S\subseteq V$, and we wish to approximate either the distances within nodes in $S$ or from nodes in $S$ to any other node. We show that there exists an $(S\times S)$-spanner of size $O(n\sqrt{|S|})$ with $f(d)=d+2$, and an $(S\times V)$-spanner of size $O(n\sqrt{|S|\log n})$ with $f(d)=d+2\log n$. All the mentioned pairwise spanners can be constructed in polynomial time.

Connected through hyperedge HE-1 (induced by source paper "weighted additive spanners"):
  with members:
    - "some general structure for extremal sparsification problems"
    - "almost shortest paths and pram distance oracles in weighted graphs"
    - "lower bounds on sparse spanners emulators and diameter reducing shortcuts"
    - "a hierarchy of lower bounds for sublinear additive spanners"
    - "linear size distance preservers"
    - "better distance preservers and additive spanners"
    - "the 4 3 additive spanner exponent is tight"
    - "additive spanners a simple construction"

Connected through hyperedge HE-2 (induced by source paper "some general structure for extremal sparsification problems"):
  with members:
    - "improved guarantees for vertex sparsification in planar graphs"
    - "reachability preservers new extremal bounds and approximation algorithms"
    - "linear size distance preservers"
    - "additive spanners a simple construction"

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 "approximation algorithms and an integer program for multi level graph spanners"):
  with members:
    - "multi level steiner trees"
    - "linear size distance preservers"
    - "directed spanners via flow based linear programs"
    - "transitive closure spanners"

Connected through hyperedge HE-5 (induced by source paper "multi level graph sketches via single level solvers"):
  with members:
    - "the sparsest additive spanner via multiple weighted bfs trees"
    - "label cover instances with large girth and the hardness of approximating basic k spanner"
    - "approximating subset k connectivity problems"

Connected through hyperedge HE-6 (induced by source paper "tight approximation algorithms for bichromatic graph diameter and related problems"):
  with members:
    - "towards tight approximation bounds for graph diameter and eccentricities"
    - "fast computation of empirically tight bounds for the diameter of massive graphs"

Connected through hyperedge HE-7 (induced by source paper "a ptas for subset tsp in minor free graphs"):
  with members:
    - "truly optimal euclidean spanners"
    - "greedy spanners are optimal in doubling metrics"
    - "on subexponential parameterized algorithms for steiner tree and directed subset tsp on planar graphs"
    - "minor free graphs have light spanners"
    - "the greedy spanner is existentially optimal"
    - "linear size distance preservers"
    - "graph minors for preserving terminal distances approximately lower and upper bounds"
    - "a light metric spanner"

Connected through hyperedge HE-8 (induced by source paper "near isometric terminal embeddings for doubling metrics"):
  with members:
    - "reachability preservers new extremal bounds and approximation algorithms"
    - "a light metric spanner"
    - "prioritized metric structures and embedding"
    - "optimal euclidean spanners really short thin and lanky"
    - "ramsey partitions and proximity data structures"
    - "fast construction of nets in low dimensional metrics and their applications"

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)