Some results regarding to the Bifurcation set for the family Double Standard Maps on the circle
Diego Lugo
Universidad Pontificia Católica de Valparaíso (Chile)
Resumen:
Let
\[f\]
a continuous map on the circle
\[\mathbb{S}^1\]
and consider for an open set
\[H\subset\mathbb{S}^1\]
the set 
\[S_H=\{\theta\in\mathbb{S}^1:\;f^n(\theta)\notin H\;\forall n\geq0\}\]
called the Surviving set for
\[H\]
. Focusing on the set of all the open intervals of the circle, the Bifurcation set
\[\mathcal{B}_f\]
$\mathcal{B}_f$ is defined to be the collection of those interval holes whose surviving set is sensitive to arbitrarily small changes of their position. 
There are interesting results for the set
\[\mathcal{B}_f\]
when the map 
\[f\]
is transitive regarding with its geometric form and topological properties. We pretend to extend this results to the non-transitive world. As an approach, we point out on the family of Double Standard maps of the circle given by the formula 
\[f_{\alpha,\beta}(\theta)=2\theta+\alpha+\frac{\beta}{\pi}\sin(2\pi\theta)(\mathrm{mod}\,1).\]
 
The principal reasons to use this family are the semiconjugacy of each member or the family with the Doubling map and its simple non-transitive form given by the presence of a single attracting or indifferent periodic orbit. Besides the set of parameters
\[\alpha,\beta\]
for which an attractting or neutral periodic orbit of fixed period exists for
\[f_{\alpha,\beta}\]
is known as an analogue of the Arnold Tongues for its family of circle diffeomorphisms (The Arnold maps or The Arnold Family).