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: "context free grammars with storage"
  Abstract: Context-free S grammars are introduced, for arbitrary (storage) type S, as a uniform framework for recursion-based grammars, automata, and transducers, viewed as pro- grams. To each occurrence of a nonterminal of a context-free S grammar an object of type S is associated, that can be acted upon by tests and operations, as indicated in the rules of the grammar. Taking particular storage types gives particular formalisms, such as indexed grammars, top-down tree transducers, attribute grammars, etc. Context-free S grammars are equivalent to pushdown S automata. The context-free S languages can be obtained from the deterministic one-way S automaton languages by way of the delta operations on languages, introduced in this paper.

Connected through hyperedge HE-1 (induced by source paper "a buchi elgot trakhtenbrot theorem for automata with mso graph storage"):
  with members:
    - "string to string interpretations with polynomial size output"
    - "origin equivalence of two way word transducers is in pspace"
    - "weighted regular tree grammars with storage"
    - "dyck based characterizations of indexed languages"
    - "transducers with origin information"
    - "mso definable string transductions and two way finite state transducers"

Connected through hyperedge HE-2 (induced by source paper "linear bounded composition of tree walking tree transducers linear size increase and complexity"):
  with members:
    - "xml navigation and transformation by tree walking automata and transducers with visible and invisible pebbles"
    - "tree automata and tree grammars"
    - "the complexity of translation membership for macro tree transducers"

Connected through hyperedge HE-3 (induced by source paper "approximation of weighted automata with storage"):
  with members:
    - "an automata characterisation for multiple context free languages"
    - "practical experiments with regular approximation of context free languages"

Connected through hyperedge HE-4 (induced by source paper "weighted regular tree grammars with storage"):
  with members:
    - "tree automata and tree grammars"

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)