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: "an entropy based proof for the moore bound for irregular graphs"
  Abstract: We provide proofs of the following theorems by considering the entropy of random walks. Theorem 1 (Alon, Hoory and Linial) Let \(G\) be an undirected simple graph with \(n\) vertices, girth \(g\), minimum degree at least \(2\) and average degree \(\bar{d}\). Odd girth If \(g=2r+1\), then \(n\ge 1+\bar{d}\displaystyle \sum _{i=0}^{r-1}(\bar{d}-1)^{i}\). Even girth If \(g=2r\), then \(n\ge 2\displaystyle \sum _{i=0}^{r-1} (\bar{d}-1)^i\). Theorem 2 (Hoory) Let \(G=(V_L,V_R,E)\) be a bipartite graph of girth \(g=2r\), with \(n_L=|V_L|\) and \(n_R=|V_R|\), minimum degree at least \(2\) and the left and right average degrees \(d_L\) and \(d_R\). Then, #R##N##R##N#$$\begin{aligned} n_L&\ge \sum _{i=0}^{r-1}(d_R-1)^{\lceil \frac{i}{2}\rceil }(d_L-1)^{\lfloor \frac{i}{2}\rfloor },\\ n_R&\ge \sum _{i=0}^{r-1}(d_L-1)^{\lceil \frac{i}{2}\rceil }(d_R-1)^{\lfloor \frac{i}{2}\rfloor }. \end{aligned}$$

Connected through hyperedge HE-1 (induced by source paper "efficient algorithms for constructing very sparse spanners and emulators"):
  with members:
    - "the greedy spanner is existentially optimal"
    - "a hierarchy of lower bounds for sublinear additive spanners"
    - "hopsets with constant hopbound and applications to approximate shortest paths"
    - "distributed strong diameter network decomposition"
    - "a linear size logarithmic stretch path reporting distance oracle for general graphs"
    - "very sparse additive spanners and emulators"
    - "the 4 3 additive spanner exponent is tight"
    - "parallel graph decompositions using random shifts"

Connected through hyperedge HE-2 (induced by source paper "set membership with a few bit probes"):
  with members:
    - "on locally decodable source coding"
    - "invertible bloom lookup tables"

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)