  The ground state of a gas of Bosons confined in an external trap potential
and interacting via repulsive two-body forces has recently been shown to
exhibit complete Bose-Einstein condensation in the dilute limit, yielding for
the first time a rigorous proof of this phenomenon in a physically realistic
setting. We give here an account of this work about the Gross-Pitaevskii limit
where the particle number $N$ goes to infinity with $Na$ fixed, where $a$ is
the scattering length of the interparticle interaction, measured in units of
the trap size.
