We also consider other SVM-based baselines: SVM+LDA, SVM+BTM, SVM+NTM, whose features are topic distributions for instances learned by LDA (Blei et al., 2003), BTM (Yan et al., 2013), and NTM (Miao et al., 2017), respectively.
bTM is one of the state-ofthe-art topic models for short texts.