@prefix : <http://www.test.com/>.
@prefix t: <http://variable.com/#>.

:mary :parent :sally, :bob, :frank, :maryjr.
:sally :parent :fran, :marshall.
:paul :parent :sally.
:bob :parent :jane.
:maryjr :parent :maryIII.
:merv :parent :bob.
:jane :parent :janeII.

this log:forAll t:x, t:y, t:z.

{t:x :parent t:y.} log:implies {t:y :child t:x}.
{t:x :parent t:y. t:y :parent t:z.} log:implies {t:x :gParent t:z. t:z :gChild t:x}.
{t:x :parent t:y. t:y :gParent t:z.} log:implies {t:x :ggParent t:z.}.