Where $ \Vert f_\tau-f_{\tau_0}\Vert_{L_1}$ = $\int_\mathbb{T} \vert f(t-\tau)-f(t-\tau_0)\vert \ dt$
I find it easy to see when f is uniformly continuous, since we would have
$\vert f_\tau-f_{\tau_0}\vert < \epsilon$ if we set $\tau$ close enough to $\tau_0$
and then $\Vert f_\tau-f_{\tau_0}\Vert_{L_1} = \int_\mathbb{T}\vert f_\tau(t)-f_{\tau_0}(t)\vert \ dt$ $~$< $~$$\int_\mathbb{T}\epsilon\ d t$ = 2$\pi\epsilon$
But I can't get to this by assuming f is only continuous
Any suggestions please?