@prefix l: <http://www.w3.org/2000/10/swap/log.n3#>.
@prefix u: <http://www.w3.org/2000/01/rdf-schema#>.

{{ :C1 u:subClassOf :C2.
   :C2 u:subClassOf :C3. }
     l:implies { :C1 u:subClassOf :C3. }
 } a l:Truth; l:forAll :C1, :C2, :C3.