For the feature-based method, we utilize all the features extractable from the PET trees that are standardly used in the state-of-the-art featurebased systems for DA of RE (Nguyen and Grishman, 2014).
the feature set employed in this paper (denoted by FET) includes: the lexical features, i.e., the context words, the head words, the bigrams, the number of words, the lexical path, the order of mention (Zhou et al., 2005;Sun et al., 2011); and the syntactic features, i.e., the path connecting the two mentions in PET and the unigrams, bigrams, trigrams along this path (Zhou et al., 2005;Jiang and Zhai, 2007a).