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 non returning regular languages"
  Abstract: A regular language $L$ is non-returning if in the minimal deterministic finite automaton accepting it there are no transitions into the initial state. Eom, Han and Jir\'askov\'a derived upper bounds on the state complexity of boolean operations and Kleene star, and proved that these bounds are tight using two different binary witnesses. They derived upper bounds for concatenation and reversal using three different ternary witnesses. These five witnesses use a total of six different transformations. We show that for each $n\ge 4$ there exists a ternary witness of state complexity $n$ that meets the bound for reversal and that at least three letters are needed to meet this bound. Moreover, the restrictions of this witness to binary alphabets meet the bounds for product, star, and boolean operations. We also derive tight upper bounds on the state complexity of binary operations that take arguments with different alphabets. We prove that the maximal syntactic semigroup of a non-returning language has $(n-1)^n$ elements and requires at least $\binom{n}{2}$ generators. We find the maximal state complexities of atoms of non-returning languages. Finally, we show that there exists a most complex non-returning language that meets the bounds for all these complexity measures.

Connected through hyperedge HE-1 (induced by source paper "towards a theory of complexity of regular languages"):
  with members:
    - "unrestricted state complexity of binary operations on regular languages"
    - "unrestricted state complexity of binary operations on regular and ideal languages"
    - "most complex regular 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-2 (induced by source paper "complexity of regular bifix free languages"):
  with members:
    - "most complex regular ideals"
    - "complexity of atoms combinatorially"
    - "theory of atomata"
    - "syntactic complexity of ideal and closed languages"
    - "decision problems for convex languages"
    - "quotient complexity of regular languages"

Connected through hyperedge HE-3 (induced by source paper "a new technique for reachability of states in concatenation automata"):
  with members:
    - "unrestricted state complexity of binary operations on regular languages"
    - "most complex regular ideal 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-4 (induced by source paper "complexity of suffix free regular languages"):
  with members:
    - "complexity of proper suffix convex regular languages"
    - "unrestricted state complexity of binary operations on regular languages"
    - "complexity of prefix convex regular languages"
    - "syntactic complexity of bifix free languages"
    - "quotient complexities of atoms in regular ideal languages"
    - "upper bounds on syntactic complexity of left and two sided ideals"
    - "complexity of atoms combinatorially"
    - "symmetric groups and quotient complexity of boolean operations"

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)