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: "approximate distance oracles with improved query time"
  Abstract: Given an undirected graph $G$ with $m$ edges, $n$ vertices, and non-negative edge weights, and given an integer $k\geq 2$, we show that a $(2k-1)$-approximate distance oracle for $G$ of size $O(kn^{1 + 1/k})$ and with $O(\log k)$ query time can be constructed in $O(\min\{kmn^{1/k},\sqrt km + kn^{1 + c/\sqrt k}\})$ time for some constant $c$. This improves the $O(k)$ query time of Thorup and Zwick. Furthermore, for any $0   0$ and $k = O(\log n/\log\log n)$.

Connected through hyperedge HE-1 (induced by source paper "almost shortest paths and pram distance oracles in weighted graphs"):
  with members:
    - "thorup zwick emulators are universally optimal hopsets"
    - "efficient algorithms for constructing very sparse spanners and emulators"
    - "a hierarchy of lower bounds for sublinear additive spanners"
    - "hopsets with constant hopbound and applications to approximate shortest paths"
    - "a linear size logarithmic stretch path reporting distance oracle for general graphs"
    - "parallel metric tree embedding based on an algebraic view on moore bellman ford"
    - "the 4 3 additive spanner exponent is tight"
    - "a deterministic almost tight distributed algorithm for approximating single source shortest paths"

Connected through hyperedge HE-2 (induced by source paper "ramsey spanning trees and their applications"):
  with members:
    - "a new efficient construction on probabilistic tree embeddings"
    - "the 4 3 additive spanner exponent is tight"
    - "approximate distance oracle with constant query time"
    - "ramsey partitions and proximity data structures"
    - "ramsey type theorems for metric spaces with applications to online problems"
    - "lower stretch spanning trees"

Connected through hyperedge HE-3 (induced by source paper "approximate distance oracles for planar graphs with improved query time space tradeoff"):
  with members:
    - "approximate distance oracle with constant query time"
    - "approximate distance oracles with improved preprocessing time"
    - "linear space approximate distance oracles for planar bounded genus and minor free graphs"
    - "exact distance oracles for planar graphs"
    - "ramsey partitions and proximity data structures"

Connected through hyperedge HE-4 (induced by source paper "efficient construction of probabilistic tree embeddings"):
  with members:
    - "a linear size logarithmic stretch path reporting distance oracle for general graphs"
    - "parallel metric tree embedding based on an algebraic view on moore bellman ford"
    - "approximate distance oracle with constant query time"
    - "improved parallel algorithms for spanners and hopsets"
    - "ramsey partitions and proximity data structures"

Connected through hyperedge HE-5 (induced by source paper "prioritized metric structures and embedding"):
  with members:
    - "a linear size logarithmic stretch path reporting distance oracle for general graphs"
    - "approximate distance oracle with constant query time"
    - "a polylogarithmic competitive algorithm for the k server problem"
    - "ramsey partitions and proximity data structures"
    - "embedding metrics into ultrametrics and graphs into spanning trees with constant average distortion"

Connected through hyperedge HE-6 (induced by source paper "hierarchical oracles for time dependent networks"):
  with members:
    - "route planning in transportation networks"
    - "distance oracles for time dependent networks"
    - "approximate distance oracles with improved preprocessing time"
    - "fast precise and dynamic distance queries"

Connected through hyperedge HE-7 (induced by source paper "engineering oracles for time dependent road networks"):
  with members:
    - "hierarchical oracles for time dependent networks"
    - "route planning in transportation networks"
    - "distance oracles for time dependent networks"
    - "approximate distance oracles with improved preprocessing time"

Connected through hyperedge HE-8 (induced by source paper "sublinear space distance labeling using hubs"):
  with members:
    - "simpler faster and shorter labels for distances in graphs"
    - "sublinear distance labeling for sparse graphs"
    - "approximate distance oracle with constant query time"
    - "on the hardness of distance oracle for sparse graph"

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.DM(Discrete Mathematics)