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 reachability for unidirectional channel systems extended with regular tests"):
  Abstract: Unidirectional channel systems (Chambart & Schnoebelen, CONCUR 2008) are#N#finite-state systems where one-way communication from a Sender to a Receiver#N#goes via one reliable and one unreliable unbounded fifo channel. While#N#reachability is decidable for these systems, equipping them with the#N#possibility of testing regular properties on the contents of channels makes it#N#undecidable. Decidability is preserved when only emptiness and nonemptiness#N#tests are considered: the proof relies on an elaborate reduction to a#N#generalized version of Post's Embedding Problem.

Includes members:
  Member "complexity hierarchies beyond elementary":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "the ideal approach to computing closed subsets in well quasi orderings")
  Member "generalized post embedding problems":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "well quasiorders and hierarchy theory")
  Member "the parametric ordinal recursive complexity of post embedding problems":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "complexity hierarchies beyond elementary")
  Member "graph logics with rational relations":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "decision procedures for path feasibility of string manipulating programs with complex operations")
  Member "the power of well structured systems":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "the ideal approach to computing closed subsets in well quasi orderings")
  Member "reachability analysis of communicating pushdown systems":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "timed basic parallel processes")
  Member "cutting through regular post embedding problems":
    also connected through other hyperedges:
      - Hyperedge HE-7 (induced by source paper "complexity hierarchies beyond elementary")
  Member "reachability of communicating timed processes":
    also connected through other hyperedges:
      - Hyperedge HE-8 (induced by source paper "timed basic parallel processes")

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.LO(Logic in Computer Science)