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: "periodicity and unbordered words a proof of the extended duval conjecture"
  Abstract: The relationship between the length of a word and the maximum length of its unbordered factors is investigated in this paper. Consider a finite word w of length n. We call a word bordered, if it has a proper prefix which is also a suffix of that word. Let f(w) denote the maximum length of all unbordered factors of w, and let p(w) denote the period of w. Clearly, f(w) < p(w)+1. #R##N#We establish that f(w) = p(w), if w has an unbordered prefix of length f(w) and n > 2f(w)-2. This bound is tight and solves the stronger version of a 21 years old conjecture by Duval. It follows from this result that, in general, n > 3f(w)-3 implies f(w) = p(w) which gives an improved bound for the question asked by Ehrenfeucht and Silberger in 1979.

Connected through hyperedge HE-1 (induced by source paper "maximal unbordered factors of random strings"):
  with members:
    - "periods and borders of random words"
    - "internal pattern matching queries in a text and applications"

Connected through hyperedge HE-2 (induced by source paper "on the number of unbordered factors"):
  with members:
    - "enumeration and decidable properties of automatic sequences"

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.DM(Discrete Mathematics)