X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/prng_gpu.git/blobdiff_plain/4bdc449d7d1ab2508a4f72db158e0130f61fe2ef..39211acd090848fea982c58fd56a95396913db0b:/prng_gpu.tex diff --git a/prng_gpu.tex b/prng_gpu.tex index 73bc958..cd8bad3 100644 --- a/prng_gpu.tex +++ b/prng_gpu.tex @@ -50,7 +50,45 @@ Interet de générer des nombres alea sur GPU Présentation des itérations chaotiques -\section{blabla} + + + +\section{The relativity of disorder} +\label{sec:de la relativité du désordre} + +\subsection{Impact of the topology's finenesse} + +Let us firstly introduce the following notations. + +\begin{notation} +$\mathcal{X}_\tau$ will denote the topological space $\left(\mathcal{X},\tau\right)$, whereas $\mathcal{V}_\tau (x)$ will be the set of all the neighborhoods of $x$ when considering the topology $\tau$ (or simply $\mathcal{V} (x)$, if there is no ambiguity). +\end{notation} + + + +\begin{theorem} +\label{Th:chaos et finesse} +Let $\mathcal{X}$ a set and $\tau, \tau'$ two topologies on $\mathcal{X}$ s.t. $\tau'$ is finer than $\tau$. Let $f:\mathcal{X} \to \mathcal{X}$, continuous both for $\tau$ and $\tau'$. + +If $(\mathcal{X}_{\tau'},f)$ is chaotic according to Devaney, then $(\mathcal{X}_\tau,f)$ is chaotic too. +\end{theorem} + +\begin{proof} +Let us firstly establish the transitivity of $(\mathcal{X}_\tau,f)$. + +Let $\omega_1, \omega_2$ two open sets of $\tau$. Then $\omega_1, \omega_2 \in \tau'$, becaus $\tau'$ is finer than $\tau$. As $f$ is $\tau'-$transitive, we can deduce that $\exists n \in \mathds{N}, \omega_1 \cap f^{(n)}(\omega_2) = \varnothing$. Consequently, $f$ is $\tau-$transitive. + +Let us now consider the regularity of $(\mathcal{X}_\tau,f)$, \emph{i.e.}, for all $x \in \mathcal{X}$, and for all $\tau-$neighborhood $V$ of $x$, there is a periodic point for $f$ into $V$. + +Let $x \in \mathcal{X}$ and $V \in \mathcal{V}_\tau (x)$ a $\tau-$neighborhood of $x$. By definition, $\exists \omega \in \tau, x \in \omega \subset V$. + +But $\tau \subset \tau'$, so $\omega \in \tau'$, and then $V \in \mathcal{V}_{\tau'} (x)$. As $(\mathcal{X}_{\tau'},f)$ is regular, there is a periodic point for $f$ into $V$, and the regularity of $(\mathcal{X}_\tau,f)$ is proven. +\end{proof} + + + + +\section{Chaos on the order topology} \subsection{The phase space is an interval of the real line}