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 the statistical analysis of practical sparql queries"):
  Abstract: In this paper, we analyze some basic features of SPARQL queries coming from our practical world in a statistical way. These features include three statistic features such as the occurrence frequency of triple patterns, fragments, well-designed patterns and four semantic features such as monotonicity, non-monotonicity, weak monotonicity (old solutions are still served as parts of new solutions when some new triples are added) and satisfiability. All these features contribute to characterize SPARQL queries in different dimensions. We hope that this statistical analysis would provide some useful observation for researchers and engineers who are interested in what practical SPARQL queries look like, so that they could develop some practical heuristics for processing SPARQL queries and build SPARQL query processing engines and benchmarks. Besides, they can narrow the scope of their problems by avoiding those cases that do possibly not happen in our practical world.

Includes members:
  Member "efficient approximation of well designed sparql queries":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "piwd a plugin based framework for well designed sparql")
  Member "on the satisfiability problem for sparql patterns":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "piwd a plugin based framework for well designed sparql")
  Member "an empirical study of real world sparql queries":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "revisiting compact rdf stores based on k2 trees")
  Member "foundations of sparql query optimization":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "towards an integrated graph algebra for graph pattern matching with gremlin extended version")
  Member "semantics and complexity of sparql":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "functional programming in pattern match oriented programming style")

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.DB(Databases)