Bernard Arnault drilled his offspring in math when young, assigned them company roles and mentors as adults, then made them joint owners of a firm empowered to run the luxury conglomerate
Bernard Arnault and wife Hélène Mercier-Arnault, center, with, from left, Alexandre, Frédéric, Jean, Delphine and Antoine Arnault.LEWIS JOLY/SIPA/ASSOCIATED PRESS
