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: "isomorphism of regular trees and words"
  Abstract: The computational complexity of the isomorphism problem for regular trees, regular linear orders, and regular words is analyzed. A tree is regular if it is isomorphic to the prefix order on a regular language. In case regular languages are represented by NFAs (DFAs), the isomorphism problem for regular trees turns out to be EXPTIME-complete (resp. P-complete). In case the input automata are acyclic NFAs (acyclic DFAs), the corresponding trees are (succinctly represented) finite trees, and the isomorphism problem turns out to be PSPACE-complete (resp. P-complete). A linear order is regular if it is isomorphic to the lexicographic order on a regular language. A polynomial time algorithm for the isomorphism problem for regular linear orders (and even regular words, which generalize the latter) given by DFAs is presented. This solves an open problem by Esik and Bloom.

Connected through hyperedge HE-1 (induced by source paper "the order type of scattered context free orderings of rank one is computable"):
  with members:
    - "on the order type of scattered context free orderings"
    - "the ordinal generated by an ordinal grammar is computable"
    - "scattered context free linear orderings"

Connected through hyperedge HE-2 (induced by source paper "the ordinal generated by an ordinal grammar is computable"):
  with members:
    - "isomorphisms of scattered automatic linear orders"
    - "scattered context free linear orderings"
    - "algebraic linear orderings"

Connected through hyperedge HE-3 (induced by source paper "pro aperiodic monoids via saturated models"):
  with members:
    - "the linear nature of pseudowords"
    - "an algebraic approach to mso definability on countable linear orderings"
    - "the sch utzenberger product for syntactic spaces"
    - "mccammond s normal forms for free aperiodic semigroups revisited"
    - "recognisable languages over monads"
    - "going higher in the first order quantifier alternation hierarchy on words"

Connected through hyperedge HE-4 (induced by source paper "circuit evaluation for finite semirings"):
  with members:
    - "evaluating matrix circuits"
    - "regular realizability problems and context free languages"
    - "parallel identity testing for skew circuits with big powers and applications"
    - "formal theories for linear algebra"

Connected through hyperedge HE-5 (induced by source paper "tree compression using string grammars"):
  with members:
    - "tree compression with top trees revisited"
    - "a really simple approximation of smallest grammar"
    - "constructing small tree grammars and small circuits for formulas"
    - "linear compressed pattern matching for polynomial rewriting extended abstract"
    - "approximation of grammar based compression via recompression"
    - "approximation of smallest linear tree grammar"
    - "faster fully compressed pattern matching by recompression"

Connected through hyperedge HE-6 (induced by source paper "processing succinct matrices and vectors"):
  with members:
    - "on the complexity of the multivariate resultant"

Connected through hyperedge HE-7 (induced by source paper "isomorphisms of scattered automatic linear orders"):
  with members:
    - "the rank of tree automatic linear orderings"
    - "automatic structures richness and limitations"

Connected through hyperedge HE-8 (induced by source paper "on context free languages of scattered words"):
  with members:
    - "context free ordinals"
    - "scattered context free linear orderings"
    - "algebraic linear orderings"

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)