usepackage{oz, amsfonts}
egin{schema}{MusicStore}
member: pset NAME
orders: pset (NAME imes ALBUM)
owns: pset (NAME imes ALBUM)
ST
{f dom}mbox{ } orders subseteq member
{f dom}mbox{ } owns subseteq member
forall (m, a)in orders.(m, a)
otin owns
end{schema}