“…Several researchers have defined tasks related to discourse structure, including sentence ordering (Chen et al, 2016;Logeswaran et al, 2016;Cui et al, 2018), sentence clustering (Wang et al, 2018b), and disentangling textual threads (Elsner andCharniak, 2008, 2010;Lowe et al, 2015;Mehri and Carenini, 2017;Jiang et al, 2018;Kummerfeld et al, 2019).…”