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: "on the positivity problem for simple linear recurrence sequences"
  Abstract: Given a linear recurrence sequence (LRS) over the integers, the Positivity Problem} asks whether all terms of the sequence are positive. We show that, for simple LRS (those whose characteristic polynomial has no repeated roots) of order 9 or less, Positivity is decidable, with complexity in the Counting Hierarchy.

Connected through hyperedge HE-1 (induced by source paper "pumping lemmas for weighted automata"):
  with members:
    - "a robust class of linear recurrence sequences"
    - "weak cost register automata are still powerful"
    - "descriptive complexity for counting complexity classes"
    - "copyless cost register automata structure expressiveness and closure properties"
    - "decision problems for additive regular functions"
    - "ultimate positivity is decidable for simple linear recurrence sequences"
    - "deciding unambiguity and sequentiality from a finitely ambiguous max plus automaton"

Connected through hyperedge HE-2 (induced by source paper "on the mortality problem from multiplicative matrix equations to linear recurrence sequences and beyond"):
  with members:
    - "on the identity problem for the special linear group and the heisenberg group"
    - "solvability of matrix exponential equations"
    - "on the skolem problem for continuous linear dynamical systems"
    - "on termination of integer linear loops"
    - "tighter undecidability bounds for matrix mortality zero in the corner problems and more"
    - "on the complexity of the orbit problem"
    - "positivity problems for low order linear recurrence sequences"

Connected through hyperedge HE-3 (induced by source paper "sequential relational decomposition"):
  with members:
    - "functional synthesis via input output separation"
    - "algorithms for synthesizing priorities in component based systems"

Connected through hyperedge HE-4 (induced by source paper "on the identity problem for the special linear group and the heisenberg group"):
  with members:
    - "on termination of integer linear loops"
    - "on the complexity of the orbit problem"
    - "ultimate positivity is decidable for simple linear recurrence sequences"

Connected through hyperedge HE-5 (induced by source paper "decision problems on unary probabilistic and quantum automata"):
  with members:
    - "classical and quantum realtime alternating automata"
    - "ultimate positivity is decidable for simple linear recurrence sequences"
    - "positivity problems for low order linear recurrence sequences"

Connected through hyperedge HE-6 (induced by source paper "decidability of the membership problem for 2 times 2 integer matrices"):
  with members:
    - "tighter undecidability bounds for matrix mortality zero in the corner problems and more"
    - "on the complexity of the orbit problem"
    - "ultimate positivity is decidable for simple linear recurrence sequences"

Connected through hyperedge HE-7 (induced by source paper "on recurrent reachability for continuous linear dynamical systems"):
  with members:
    - "on the decidability of the bounded continuous skolem problem"

Connected through hyperedge HE-8 (induced by source paper "ultimate positivity is decidable for simple linear recurrence sequences"):
  with members:
    - "positivity problems for low order linear recurrence sequences"
    - "orbits of linear maps and regular languages"

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)