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 "separability by piecewise testable languages is ptime complete"):
  Abstract: Piecewise testable languages form the first level of the Straubing-Th\'erien hierarchy. The membership problem for this level is decidable and testing if the language of a DFA is piecewise testable is NL-complete. The question has not yet been addressed for NFAs. We fill in this gap by showing that it is PSpace-complete. The main result is then the lower-bound complexity of separability of regular languages by piecewise testable languages. Two regular languages are separable by a piecewise testable language if the piecewise testable language includes one of them and is disjoint from the other. For languages represented by NFAs, separability by piecewise testable languages is known to be decidable in PTime. We show that it is PTime-hard and that it remains PTime-hard even for minimal DFAs.

Includes members:
  Member "piecewise testable languages and nondeterministic automata":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "partially ordered automata and piecewise testability")
  Member "going higher in the first order quantifier alternation hierarchy on words":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "on all things star free")
  Member "separating regular languages by piecewise testable and unambiguous languages":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "partially ordered automata and piecewise testability")
  Member "efficient separability of regular languages by subsequences and suffixes":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "partially ordered automata and piecewise testability")
  Member "piecewise testable tree languages":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "partially ordered automata and piecewise testability")
  Member "around dot depth one":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "adding successor a transfer theorem for separation and covering")

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.FL(Formal Languages and Automata Theory)