Project(Filter((?cat = ?show),
               Join(Project(Union(BGP( ?show ?y <http://www.wawser.com/cat/2>),
                                  BGP( ?x ?y <http://www.wawser.com/cat/2> .
                                       ?show ?y ?x)),
                            {?show}),
                    BGP( ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.semantic.wawser.com/eventos> .
                         ?x <http://www.types.wawser.com/cat> ?cat .
                         ?x <http://purl.org/dc/elements/1.1/title> ?titulo))),
        {?titulo})