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 "using bounded model checking to focus fixpoint iterations"):
  Abstract: Two classical sources of imprecision in static analysis by abstract interpretation are widening and merge operations. Merge operations can be done away by distinguishing paths, as in trace partitioning, at the expense of enumerating an exponential number of paths. In this article, we describe how to avoid such systematic exploration by focusing on a single path at a time, designated by SMT-solving. Our method combines well with acceleration techniques, thus doing away with widenings as well in some cases. We illustrate it over the well-known domain of convex polyhedra.

Includes members:
  Member "improving strategies via smt solving":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "safety verification and refutation by k invariants and k induction extended version")
  Member "automatic modular abstractions for template numerical constraints":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "program analysis with local policy iteration")
  Member "automatic modular abstractions for linear constraints":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "compositional invariant generation via linear recurrence analysis")
  Member "symbolic methods to enhance the precision of numerical abstract domains":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "automatically proving microkernels free from privilege escalation from their executable")
  Member "a static analyzer for large safety critical software":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "automatically proving microkernels free from privilege escalation from their executable")

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.PL(Programming Languages)