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: "lattices of logical fragments over words"
  Abstract: This paper introduces an abstract notion of fragments of monadic second-order logic. This concept is based on purely syntactic closure properties. We show that over finite words, every logical fragment defines a lattice of languages with certain closure properties. Among these closure properties are residuals and inverse C-morphisms. Here, depending on certain closure properties of the fragment, C is the family of arbitrary, non-erasing, length-preserving, length-multiplying, or length-reducing morphisms. In particular, definability in a certain fragment can often be characterized in terms of the syntactic morphism. This work extends a result of Straubing in which he investigated certain restrictions of first-order logic formulae. In contrast to Straubing's model-theoretic approach, our notion of a logical fragment is purely syntactic and it does not rely on Ehrenfeucht-Fraisse games. #R##N#As motivating examples, we present (1) a fragment which captures the stutter-invariant part of piecewise-testable languages and (2) an acyclic fragment of Sigma_2. As it turns out, the latter has the same expressive power as two-variable first-order logic FO^2.

Connected through hyperedge HE-1 (induced by source paper "monadic second order logic with arbitrary monadic predicates"):
  with members:
    - "a myhill nerode theorem for automata with advice"

Connected through hyperedge HE-2 (induced by source paper "one quantifier alternation in first order logic with modular predicates"):
  with members:
    - "the join levels of the trotter weil hierarchy are decidable"
    - "on logical hierarchies withinfoâ definable languages"

Connected through hyperedge HE-3 (induced by source paper "the fo2 alternation hierarchy is decidable"):
  with members:
    - "the join levels of the trotter weil hierarchy are decidable"
    - "languages of dot depth one over infinite words"
    - "an introduction to finite automata and their connection to logic"
    - "on fo 2 quantifier alternation over words"
    - "structure theorem and strict alternation hierarchy for fo2 on words"
    - "logic meets algebra the case of regular languages"

Connected through hyperedge HE-4 (induced by source paper "quantifier alternation in two variable first order logic with successor is decidable"):
  with members:
    - "the join levels of the trotter weil hierarchy are decidable"
    - "the fo2 alternation hierarchy is decidable"
    - "around dot depth one"
    - "structure theorem and strict alternation hierarchy for fo2 on words"

Connected through hyperedge HE-5 (induced by source paper "on logical hierarchies withinfoâ definable languages"):
  with members:
    - "structure theorem and strict alternation hierarchy for fo2 on words"
    - "logic meets algebra the case of regular languages"
    - "the succinctness of first order logic on linear orders"

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)