Like the majority of TS methods (Hearst, 1994; Brants et al., 2002; Misra et al., 2009;<cite> Riedl and Biemann, 2012)</cite> , in this work we focus on linear segmentation of text, but there is also a solid body of work on hierarchical TS, where each toplevel segment is further broken down (Yaari, 1997; Eisenstein, 2009 ).