## Density of hyperbolicity in dimension one.(English)Zbl 1138.37013

The authors investigate one of the central problems in dynamical systems – density of hyperbolicity in $$C^k$$ topology – which is the second part of Smale’s eleventh problem for the 21st century. The main result of the paper is: Any real polynomial can be approximated by hyperbolic real polynomials of the same degree.
Here the authors say that a real polynomial is hyperbolic or Axiom A, if the real line is the union of a repelling hyperbolic set, the basin of hyperbolic attracting periodic points and the basin of infinity. The working tool in proving the main theorem is the existence of the so called box mappings and their properties.

### MSC:

 37D20 Uniformly hyperbolic systems (expanding, Anosov, Axiom A, etc.) 37E05 Dynamical systems involving maps of the interval 37F10 Dynamics of complex polynomials, rational maps, entire and meromorphic functions; Fatou and Julia sets 37F20 Combinatorics and topology in relation with holomorphic dynamical systems
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