human: Given a node-centered hypergraph: <hypergraph>, where nodes represent papers and hyperedges represent groups of papers sharing a common citing paper.

Details of the hypergraph:
Center node: ""UNIVERSAL" CONSTRUCTION OF ARTSTEIN'S THEOREM ON NONLINEAR STABILIZATION 1"
  Abstract: Report SYCON-89-03 ABSTRACT This note presents an explicit proof of the theorem -due to Artstein- which states that the existence of a smooth control-Lyapunov function implies smooth stabilizability. More- over, the result is extended to the real-analytic and rational cases as well. The proof uses a "universal" formula given by an algebraic function of Lie derivatives; this formula originates in the solution of a simple Riccati equation.

Connected through hyperedge HE-1 (induced by source paper "FEEDBACK STABILIZATION OF NONLINEAR SYSTEMS"):
  with members:
    - "FEEDBACK STABILIZATION USING TWO-HIDDEN-LAYER NETS"
    - "FURTHER FACTS ABOUT INPUT TO STATE STABILIZATION "Further facts about input to state stabilization", IEEE"

Connected through hyperedge HE-2 (induced by source paper "Asymptotic Controllability Implies Feedback Stabilization"):
  with members:
    - "A REMARK ON ROBUST STABILIZATION OF GENERAL ASYMPTOTICALLY CONTROLLABLE SYSTEMS"
    - "CONTROL-LYAPUNOV FUNCTIONS FOR TIME-VARYING SET STABILIZATION"

Connected through hyperedge HE-3 (induced by source paper "GENERAL CLASSES OF CONTROL-LYAPUNOV FUNCTIONS"):
  with members:
    (none)

Question: Please tell me which class the center node belongs to. The 7 classes are: Neural_Networks, Reinforcement_Learning, Probabilistic_Methods, Theory, Genetic_Algorithms, Case_Based, Rule_Learning. Directly output the class name.

gpt: Neural_Networks