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: "eilenberg theorems for free"
  Abstract: Eilenberg-type correspondences, relating varieties of languages (e.g. of finite words, infinite words, or trees) to pseudovarieties of finite algebras, form the backbone of algebraic language theory. Numerous such correspondences are known in the literature. We demonstrate that they all arise from the same recipe: one models languages and the algebras recognizing them by monads on an algebraic category, and applies a Stone-type duality. Our main contribution is a variety theorem that covers e.g. Wilke's and Pin's work on $\infty$-languages, the variety theorem for cost functions of Daviaud, Kuperberg, and Pin, and unifies the two previous categorical approaches of Boja\'nczyk and of Ad\'amek et al. In addition we derive a number of new results, including an extension of the local variety theorem of Gehrke, Grigorieff, and Pin from finite to infinite words.

Connected through hyperedge HE-1 (induced by source paper "automata learning an algebraic approach"):
  with members:
    - "tree automata as algebras minimisation and determinisation"
    - "coalgebra learning via duality"
    - "generic partition refinement and weighted tree automata"
    - "efficient coalgebraic partition refinement"
    - "learning nominal automata"
    - "calf categorical automata learning framework"
    - "learning automata with side effects"
    - "syntactic monoids in a category"

Connected through hyperedge HE-2 (induced by source paper "varieties of data languages"):
  with members:
    - "equational axiomatization of algebras with structure"
    - "unveiling eilenberg type correspondences birkhoff s theorem for finite algebras duality"
    - "regular behaviours with names"
    - "generalized eilenberg theorem i local varieties of languages"
    - "automata theory in nominal sets"

Connected through hyperedge HE-3 (induced by source paper "equational axiomatization of algebras with structure"):
  with members:
    - "on the axiomatizability of quantitative algebras"
    - "unveiling eilenberg type correspondences birkhoff s theorem for finite algebras duality"
    - "regular behaviours with names"
    - "profinite monads profinite equations and reiterman s theorem"

Connected through hyperedge HE-4 (induced by source paper "syntactic structures of regular languages"):
  with members:
    - "one eilenberg theorem to rule them all"
    - "recognisable languages over monads"
    - "varieties of languages in a category"
    - "profinite monads profinite equations and reiterman s theorem"
    - "generalized eilenberg theorem i local varieties of languages"
    - "on varieties of automata enriched with an algebraic structure extended abstract"
    - "proceedings 14th international conference on automata and formal 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)