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: "almost all even yao yao graphs are spanners"
  Abstract: It is an open problem whether Yao-Yao graphs YYk (also known as sparse-Yao graphs) are all spanners when the integer parameter k is large enough. In this paper we show that, for any integer k ≥ 42, the Yao-Yao graph YY2k is a tk-spanner, with stretch factor tk = 6.03 +O(k −1) when k tends to infinity. Our result generalizes the best known result which asserts that all YY6k are spanners for k ≥ 6 [Bauer and Damian, SODA’13]. Our proof is also somewhat simpler.

Connected through hyperedge HE-1 (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"
    - "the greedy spanner is existentially optimal"
    - "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-2 (induced by source paper "spanning properties of theta theta 6"):
  with members:
    - "on the spanning and routing ratio of theta four"
    - "odd yao yao graphs are not spanners"
    - "the θ 5 graph is a spanner"
    - "towards tight bounds on theta graphs"
    - "new and improved spanning ratios for yao graphs"
    - "an infinite class of sparse yao spanners"
    - "π 2 angle yao graphs are spanners"

Connected through hyperedge HE-3 (induced by source paper "odd yao yao graphs may not be spanners"):
  with members:
    - "a simple yao yao based spanner of bounded degree"
    - "beta skeletons have unbounded dilation"

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)