$\def\Rr{\mathbb{R}}$
$\def\Cc{\mathbb C}$
$\def\Zz{\mathbb Z}$
$\def\Nn{\mathbb N}$
$\def\L{\cal L}$
$\def\M{\cal M}$
$\def\C{\cal C}$
$\def\Int{\displaystyle\int}$
$\def\Frac{\displaystyle\frac}$
$\def\d{\textrm{d}}$
$\def\tq{,\ }$
$\def\Sum{\displaystyle\sum}$
$\def\ninfini{\mathrel{\mathop{\kern 0pt \longrightarrow}\limits_{n\to \infty }}}$
$\def\Equ{\Longleftrightarrow}$
Juin 2020