Realizing arbitrary $d$-dimensional dynamics by renormalization of $C^d$-perturbations of identity
<p style='text-indent:20px;'>Any <inline-formula><tex-math id="M3">\begin{document}$ C^d $\end{document}</tex-math></inline-formula> conservative map <inline-formula><tex-math id="M4">\begin{document}$ f $\end{document}</tex-math></inline-formula> of the <inline-formula><tex-math id="M5">\begin{document}$ d $\end{document}</tex-math></inline-formula>-dimensional unit ball <inline-formula><tex-math id="M6">\begin{document}$ {\mathbb B}^d $\end{document}</tex-math></inline-formula>, <inline-formula><tex-math id="M7">\begin{document}$ d\geq 2 $\end{document}</tex-math></inline-formula>, can be realized by renormalized iteration of a <inline-formula><tex-math id="M8">\begin{document}$ C^d $\end{document}</tex-math></inline-formula> perturbation of identity: there exists a conservative diffeomorphism of <inline-formula><tex-math id="M9">\begin{document}$ {\mathbb B}^d $\end{document}</tex-math></inline-formula>, arbitrarily close to identity in the <inline-formula><tex-math id="M10">\begin{document}$ C^d $\end{document}</tex-math></inline-formula> topology, that has a periodic disc on which the return dynamics after a <inline-formula><tex-math id="M11">\begin{document}$ C^d $\end{document}</tex-math></inline-formula> change of coordinates is exactly <inline-formula><tex-math id="M12">\begin{document}$ f $\end{document}</tex-math></inline-formula>.</p>