@prefix : <http://www.w3.org/2002/08/LX/RDF/v2#> .
     @prefix log: <http://www.w3.org/2000/10/swap/log#> .
    
      [      a :TrueSentence;
             :exivar <#_gX>;
             :subformula  [
                 :objectTerm <#_gX>;
                 :predicate <http://example.com/#b>;
                 :subject <http://example.com/#a> ] ].