Deduced property

Sorry if my question is very naive, but I'm stuck on this for a while
if I go to examples in the document
http://www.w3.org/TR/2009/WD-owl2-primer-20090421/
I just want to add the following axiom (expressed here in my syntax)
if
?s :hasParent  ?f
Then
?s :hasAncestor ?f

I've checked a lot of documents and I don't figure how to do it (directly
in XML/RDF or interactively with Protégé)

Thank you in adavnace for your help

--
Jean-Claude