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 "on approximating tree spanners that are breadth first search trees"):
  Abstract: There are known efficient algorithms that approximate the minimum t for which a graph admits a tree t-spanner with ratio O ( log ? n ) . Unless there is an algorithm that decides 3-SAT in quasi-polynomial time, it is impossible to approximate efficiently the minimum t for which a graph admits a tree t-spanner that is a breadth first search tree starting from a given vertex with ratio almost o ( log ? n ) . NP-completeness of diameter at most t + 1 tree t-spanner problem is used.Tree spanners that are BFS trees may not be approximated within log factor.Known upper bound for approximation ratio is almost reached.

Includes members:
  Member "tree spanners of bounded degree graphs":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "tree 3 spanners of diameter at most 5")
  Member "tree spanners of small diameter":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "tree spanners of bounded degree graphs")
  Member "nearly linear time algorithms for graph partitioning graph sparsification and solving linear systems":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "compressive sensing for cut improvement and local clustering")

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.CC(Computational Complexity)