[002N] Construction 4.4.1·b (From classes of families to classes of sets).

Conversely to Construction 4.4.1·a [002M] we may take a class of families of sets $\mathfrak{F}$ to the the class of sets $\mathfrak{F}\Sub{1}\subseteq{\mathscr{M}}$ spanned by sets $S$ such that the singleton family $\brc{S}$ lies in $\mathfrak{C}$.