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: "the computational complexity of universality problems for prefixes suffixes factors and subwords of regular languages"
  Abstract: In this paper we consider the computational complexity of the following problems: given a DFA or NFA representing a regular language L over a finite alphabet Sigma is the set of all prefixes (resp., suffixes, factors, subwords) of all words of L equal to Sigma*? In the case of testing universality for factors of languages represented by DFA's, we find an interesting connection to Cerny's conjecture on synchronizing words.

Connected through hyperedge HE-1 (induced by source paper "scattered factor universality of words"):
  with members:
    - "k spectra of weakly c balanced words"
    - "languages ordered by the subword order"
    - "computing the k binomial complexity of the thue morse word"
    - "testing simon s congruence"
    - "multivariate fine grained complexity of longest common subsequence"
    - "decidability complexity and expressiveness of first order logic over the subword ordering"
    - "complexity of universality and related problems for partially ordered nfas"
    - "the complexity of downward closure comparisons"

Connected through hyperedge HE-2 (induced by source paper "existential length universality"):
  with members:
    - "green s relations in finite transformation semigroups"
    - "the complexity of downward closure comparisons"
    - "subclasses of presburger arithmetic and the weak exp hierarchy"
    - "emptiness and universality problems in timed automata with positive frequency"

Connected through hyperedge HE-3 (induced by source paper "complexity of universality and related problems for partially ordered nfas"):
  with members:
    - "separating regular languages with two quantifier alternations"
    - "piecewise testable languages and nondeterministic automata"

Connected through hyperedge HE-4 (induced by source paper "on the state complexity of closures and interiors of regular languages with subwords and superwords"):
  with members:
    - "decidability in the logic of subsequences and supersequences"
    - "refinement and difference for probabilistic automata"
    - "finite automata for the sub and superword closure of cfls descriptional and computational complexity"
    - "alternating towers and piecewise testable separators"
    - "the power of priority channel systems"
    - "computing downward closures for stacked counter automata"
    - "quotient complexity of ideal languages"
    - "decision problems for convex languages"

Connected through hyperedge HE-5 (induced by source paper "on non complete sets and restivo s conjecture"):
  with members:
    - "on the minimal uncompletable word problem"

Connected through hyperedge HE-6 (induced by source paper "on nfas where all states are final initial or both"):
  with members:
    - "decision problems for convex languages"

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)