In the early days of DE, rulebased approaches leveraged linguistic cues observed in definitional data (Rebeyrolle and Tanguy, 2000;Klavans and Muresan, 2001;Malaisé et al., 2004;Saggion and Gaizauskas, 2004;Storrer and Wellinghoff, 2006).
in order to deal with problems like language dependence and domain specificity, machine learning was incorporated in more recent contributions (Del Gaudio et al., 2013), which focused on encoding informative lexico-syntactic patterns in feature vectors (Cui et al., 2005;Fahmi and Bouma, 2006;Westerhout and Monachesi, 2007;Borg et al., 2009), both in supervised and semi-supervised settings (Reiplinger et al., 2012;.