Our main purpose in studying computational approaches to the detection of ancillary information is its practical application to PI.
given a pair of sentences (in general two texts), we define ATFs as ancillary information if their semantics: (i) only appears in one of the two sentences and (ii) does not change the main meaning of the sentence, i.e., either the sentences are paraphrases or, if they are not, such ATFs are not the reason for their different meaning.