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: "from regexes to parsing expression grammars"
  Abstract: Most scripting languages nowadays use regex pattern-matching libraries. These regex libraries borrow the syntax of regular expressions, but have an informal semantics that is different from the semantics of regular expressions, removing the commutativity of alternation and adding ad-hoc extensions that cannot be expressed by formalisms for efficient recognition of regular languages, such as deterministic finite automata. Parsing expression grammars are a formalism that can describe all deterministic context-free languages and have a simple computational model. In this paper, we present a formalization of regexes via transformation to parsing expression grammars. The proposed transformation easily accommodates several common regex extensions, giving a formal meaning to them. It also provides a clear computational model that helps to estimate the efficiency of regex-based matchers, and a basis for specifying provably correct optimizations for them.

Connected through hyperedge HE-1 (induced by source paper "linear parsing expression grammars"):
  with members:
    - "nez practical open grammar language"

Connected through hyperedge HE-2 (induced by source paper "analyzing catastrophic backtracking behavior in practical regular expression matching"):
  with members:
    - "static analysis for regular expression denial of service attacks"
    - "general algorithms for testing the ambiguity of finite automata"

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)