We denote $\tau = \widehat{(-1)\,1\,\mathrm{i}}$. The map $f\in\mathcal{E}$ satisfies $Tf = f$ and $f([0,1])\subset\mathbf{C}$. We denote by $\mathbf{Z}\left[\frac{1}{2}\right]$ the set of rationals of the form $\frac{k}{2^n}$ where $k\in\mathbf{Z}$ and $n\in\mathbf{N}$.
a) Show that $f\left([0,1]\cap\mathbf{Z}\left[\frac{1}{2}\right]\right)\subset\tau$.
b) Show that $f([0,1])\subset\tau$.