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: "most complex regular ideal languages"
  Abstract: A right ideal (left ideal, two-sided ideal) is a non-empty language $L$ over an alphabet $\Sigma$ such that $L=L\Sigma^*$ ($L=\Sigma^*L$, $L=\Sigma^*L\Sigma^*$). Let $k=3$ for right ideals, 4 for left ideals and 5 for two-sided ideals. We show that there exist sequences ($L_n \mid n \ge k $) of right, left, and two-sided regular ideals, where $L_n$ has quotient complexity (state complexity) $n$, such that $L_n$ is most complex in its class under the following measures of complexity: the size of the syntactic semigroup, the quotient complexities of the left quotients of $L_n$, the number of atoms (intersections of complemented and uncomplemented left quotients), the quotient complexities of the atoms, and the quotient complexities of reversal, star, product (concatenation), and all binary boolean operations. In that sense, these ideals are "most complex" languages in their classes, or "universal witnesses" to the complexity of the various operations.

Connected through hyperedge HE-1 (induced by source paper "primitivity uniform minimality and state complexity of boolean operations"):
  with members:
    - "unrestricted state complexity of binary operations on regular languages"
    - "unrestricted state complexity of binary operations on regular and ideal languages"
    - "a survey on operational state complexity"
    - "symmetric groups and quotient complexity of boolean operations"
    - "quotient complexity of star free languages"
    - "quotient complexity of ideal languages"
    - "quotient complexity of regular languages"

Connected through hyperedge HE-2 (induced by source paper "towards a theory of complexity of regular languages"):
  with members:
    - "most complex non returning regular languages"
    - "unrestricted state complexity of binary operations on regular languages"
    - "unrestricted state complexity of binary operations on regular and ideal languages"
    - "syntactic complexity of regular ideals"
    - "maximally atomic languages"
    - "upper bounds on syntactic complexity of left and two sided ideals"
    - "complexity of atoms combinatorially"
    - "symmetric groups and quotient complexity of boolean operations"

Connected through hyperedge HE-3 (induced by source paper "most complex deterministic union free regular languages"):
  with members:
    - "a new technique for reachability of states in concatenation automata"
    - "unrestricted state complexity of binary operations on regular and ideal languages"
    - "quotient complexities of atoms in regular ideal languages"
    - "complexity of atoms combinatorially"
    - "symmetric groups and quotient complexity of boolean operations"
    - "large aperiodic semigroups"
    - "theory of atomata"

Connected through hyperedge HE-4 (induced by source paper "a new technique for reachability of states in concatenation automata"):
  with members:
    - "most complex non returning regular languages"
    - "unrestricted state complexity of binary operations on regular languages"
    - "quotient complexity of star free languages"
    - "complexity in prefix free regular languages"
    - "quotient complexity of ideal languages"
    - "quotient complexity of closed languages"

Connected through hyperedge HE-5 (induced by source paper "complexity of left ideal suffix closed and suffix free regular languages"):
  with members:
    - "unrestricted state complexity of binary operations on regular languages"
    - "unrestricted state complexity of binary operations on regular and ideal languages"
    - "quotient complexities of atoms in regular ideal languages"
    - "syntactic complexity of regular ideals"
    - "upper bounds on syntactic complexity of left and two sided ideals"
    - "complexity of atoms combinatorially"
    - "symmetric groups and quotient complexity of boolean operations"
    - "quotient complexities of atoms of regular languages"

Connected through hyperedge HE-6 (induced by source paper "complexity of prefix convex regular languages"):
  with members:
    - "unrestricted state complexity of binary operations on regular languages"
    - "quotient complexities of atoms in regular ideal languages"
    - "syntactic complexity of regular ideals"
    - "maximally atomic languages"
    - "complexity of atoms combinatorially"
    - "symmetric groups and quotient complexity of boolean operations"
    - "quotient complexities of atoms of regular languages"
    - "theory of atomata"

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)