human: Given a node-centered hypergraph: <hypergraph>, where nodes represent papers and hyperedges represent sets of papers co-cited by a source paper.

Details of the hypergraph:
Center node: "on the complexity of the equivalence problem for probabilistic automata"
  Abstract: Checking two probabilistic automata for equivalence has been shown to be a key problem for efficiently establishing various behavioural and anonymity properties of probabilistic systems. In recent experiments a randomised equivalence test based on polynomial identity testing outperformed deterministic algorithms. In this paper we show that polynomial identity testing yields efficient algorithms for various generalisations of the equivalence problem. First, we provide a randomized NC procedure that also outputs a counterexample trace in case of inequivalence. Second, we show how to check for equivalence two probabilistic automata with (cumulative) rewards. Our algorithm runs in deterministic polynomial time, if the number of reward counters is fixed. Finally we show that the equivalence problem for probabilistic visibly pushdown automata is logspace equivalent to the Arithmetic Circuit Identity Testing problem, which is to decide whether a polynomial represented by an arithmetic circuit is identically zero.

Connected through hyperedge HE-1 (induced by source paper "relations on words"):
  with members:
    - "on the index of simon s congruence for piecewise testability"
    - "testing k binomial equivalence"
    - "a new approach to the 2 regularity of the ell abelian complexity of 2 automatic sequences"
    - "avoiding 2 binomial squares and cubes"
    - "fixed points avoiding abelian k powers"
    - "avoiding three consecutive blocks of the same size and same sum"

Connected through hyperedge HE-2 (induced by source paper "bisimulation equivalence of first order grammars"):
  with members:
    - "complexity hierarchies beyond elementary"
    - "dividing line between decidable pda s and undecidable ones"
    - "branching bisimilarity checking for prs"
    - "bisimilarity on basic process algebra is in 2 exptime an explicit proof"
    - "bpa bisimilarity is exptime hard"
    - "the bisimulation problem for equational graphs of finite out degree"

Connected through hyperedge HE-3 (induced by source paper "when equivalence and bisimulation join forces in probabilistic automata"):
  with members:
    - "deciding probabilistic automata weak bisimulation in polynomial time"
    - "algorithms for game metrics"
    - "approximating a behavioural pseudometric without discount for probabilistic systems"

Question: Please tell me which class the center node 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)