“…There have been many efforts for open relation learning, including pattern extraction (Banko et al, 2007;Fader et al, 2011;Mausam et al, 2012;Del Corro and Gemulla, 2013;Angeli et al, 2015;Petroni et al, 2015;Stanovsky and Dagan, 2016;Mausam, 2016;Cui et al, 2018), relation discovery (Yao et al, 2011;Marcheggiani and Titov, 2016), relation clustering (Shinyama and Sekine, 2006;Elsahar et al, 2017;Wu et al, 2019), and data collection (Riloff et al, 1999;Etzioni et al, 2005;Pantel and Pennacchiotti, 2006;Rozenfeld and Feldman, 2008;Nakashole et al, 2011;Zhu et al, 2009;Gao et al, 2020). However, for continual relation learning, there are still only some preliminary explorations for it.…”