@prefix : <http://www.w3.org/2002/08/LX/RDF/v2#> .
     @prefix log: <http://www.w3.org/2000/10/swap/log#> .
    
      [      a :TrueSentence;
             :subformula  [
                 :negated  [
                     :objectTerm <http://example.com/#X>;
                     :predicateTerm  [
                         :denotation <http://example.com/#b> ];
                     :subjectTerm  [
                         :denotation <http://example.com/#a> ] ] ];
             :univar <http://example.com/#X> ].