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: "a general framework for the derivation of regular expressions"
  Abstract: The aim of this paper is to design a theoretical framework that allows us to perform the computation of regular expression derivatives through a space of generic structures. Thanks to this formalism, the main properties of regular expression derivation, such as the finiteness of the set of derivatives, need only be stated and proved one time, at the top level. Moreover, it is shown how to construct an alternating automaton associated with the derivation of a regular expression in this general framework. Finally, Brzozowski’s derivation and Antimirov’s derivation turn out to be a particular case of this general scheme and it is shown how to construct a DFA, a NFA and an AFA for both of these derivations.

Connected through hyperedge HE-1 (induced by source paper "solving of regular equations revisited extended version"):
  with members:
    - "derivative based diagnosis of regular expression ambiguity"
    - "derivatives for enhanced regular expressions"
    - "automata and rational expressions"
    - "from finite automata to regular expressions and back a summary on descriptional complexity"
    - "state elimination ordering strategies some experimental results"

Connected through hyperedge HE-2 (induced by source paper "partial derivatives for context free languages from mu regular expressions to pushdown automata"):
  with members:
    - "on the complexity and performance of parsing with derivatives"
    - "derivatives for enhanced regular expressions"

Connected through hyperedge HE-3 (induced by source paper "derivatives for enhanced regular expressions"):
  with members:
    - "forkable regular expressions"

Connected through hyperedge HE-4 (induced by source paper "constrained expressions and their derivatives"):
  with members:
    - "two sided derivatives for regular expressions and for hairpin expressions"
    - "deciding kat and hoare logic with derivatives"
    - "derivatives of approximate regular expressions"

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)