For the version of the corpus expanded with WordNet synsets, the matching is performed based on unigrams of synsets.
the number of common synsets of the source and suspicious documents is computed and then normalised by the total number of synsets in both suspicious and source documents, using the Jaccard coefficient: (2) In plagiarism detection tasks, it is essential to perform initial filtering with superficial techniques to reduce the number of potential source documents, and therefore the number of document pairs to be processed in the next stage.