Modifying relationships
TextChart extracts relationships between entities through the use of predicate-subject-object (PSO) types that identify those relationships. It uses relational semantic vectors to designate words or small phrases as predicates.
For example, the TextChart dictionaries might associate a relational semantic vector like "interviewed" with a number of lexical entries:
<lex><word>interview</word><sv><interviewed/></sv></lex>
<lex><word>interviews</word><sv><interviewed/></sv></lex>
<lex><word>interviewing</word><sv><interviewed/></sv></lex>
<lex><word>interviewed</word><sv><interviewed/></sv></lex>
<lex><word>interrogate</word><sv><interviewed/></sv></lex>
<lex><word>interrogates</word><sv><interviewed/></sv></lex>
<lex><word>interrogating</word><sv><interviewed/></sv></lex>
<lex><word>interrogated</word><sv><interviewed/></sv></lex>
If TextChart tags all of these words in a document with the "interviewed" semantic vector, then a relationship will be extracted any time one of them appears as a predicate in context with two entities.
During David Frost's interview of former President Richard Nixon, Frost very bluntly asked why he didn't burn the tapes.
In the example phrase above, both "David Frost" and "Richard Nixon" are extracted as PERSON entities. A PERSON to PERSON relationship is also extracted, because the predicate "interview" is tagged with the "interviewed" relational semantic vector.
In PSO terms, the subject of the relationship is "David Frost", the object is "Richard Nixon", and the predicate is "interview".