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: "deterministic regular expressions with back references"
  Abstract: Most modern libraries for regular expression matching allow back-references (i.e., repetition operators) that substantially increase expressive power, but also lead to intractability. In order to find a better balance between expressiveness and tractability, we combine these with the notion of determinism for regular expressions used in XML DTDs and XML Schema. This includes the definition of a suitable automaton model, and a generalization of the Glushkov construction. We demonstrate that, compared to their non-deterministic superclass, these deterministic regular expressions with back-references have desirable algorithmic properties (i.e., efficiently solvable membership problem and some decidable problems in static analysis), while, at the same time, their expressive power exceeds that of deterministic regular expressions without back-references.

Connected through hyperedge HE-1 (induced by source paper "the theory of concatenation over finite models"):
  with members:
    - "dynamic complexity of document spanners"
    - "matching patterns with variables"
    - "weight annotation in information extraction"
    - "constant delay enumeration for nondeterministic document spanners"
    - "split correctness in information extraction"
    - "constant delay algorithms for regular document spanners"
    - "the hardness of solving simple word equations"
    - "decidability complexity and expressiveness of first order logic over the subword ordering"

Connected through hyperedge HE-2 (induced by source paper "conjunctive regular path queries with string variables"):
  with members:
    - "boundedness of conjunctive regular path queries"
    - "a trichotomy for regular trail queries"
    - "split correctness in information extraction"
    - "an analytical study of large sparql query logs"
    - "joining extractions of regular expressions"
    - "foundations of modern query languages for graph databases"

Connected through hyperedge HE-3 (induced by source paper "the teaching complexity of erasing pattern languages with bounded variable frequency"):
  with members:
    - "an overview of machine teaching"
    - "preference based teaching"

Connected through hyperedge HE-4 (induced by source paper "graph and string parameters connections between pathwidth cutwidth and the locality number"):
  with members:
    - "rounding semidefinite programming hierarchies via global correlation"
    - "reductions between expansion problems"

Connected through hyperedge HE-5 (induced by source paper "regular expressions with backreferences polynomial time matching techniques"):
  with members:
    - "a trichotomy for regular simple path queries on graphs"

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)