human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge is induced by one source paper and its member nodes are the cited papers.

Details of the hypergraph:
Center hyperedge (induced by source paper "tree 3 spanners of diameter at most 5"):
  Abstract: Tree spanners approximate distances within graphs; a subtree of a graph is a tree $t$-spanner of the graph if and only if for every pair of vertices their distance in the subtree is at most $t$ times their distance in the graph. When a graph contains a subtree of diameter at most $t$, then trivially admits a tree $t$-spanner. Now, determining whether a graph admits a tree $t$-spanner of diameter at most $t+1$ is an NP complete problem, when $t\geq 4$, and it is tractable, when $t\leq 3$. Although it is not known whether it is tractable to decide graphs that admit a tree 3-spanner of any diameter, an efficient algorithm to determine graphs that admit a tree 3-spanner of diameter at most 5 is presented. Moreover, it is proved that if a graph of diameter at most 3 admits a tee 3-spanner, then it admits a tree 3-spanner of diameter at most 5. Hence, this algorithm decides tree 3-spanner admissibility of diameter at most 3 graphs.

Includes members:
  Member "tree spanners of bounded degree graphs":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "on approximating tree spanners that are breadth first search trees")
  Member "tree spanners of small diameter":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "tree spanners of bounded degree graphs")

Question: Please tell me which class the source paper 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)