Submodular functions have been applied to a wide variety of problems in machine learning (Iyer and Bilmes, 2013; Jegelka and Bilmes, 2011; Krause and Guestrin, 2011;Kolmogorov and Zabih, 2002) and have recently attracted much attention in several NLP tasks including document summarization (Lin and Bilmes, 2011), data selection in machine translation (Kirchhoff and Bilmes, 2014) and goal-oriented chatbot training (Dimovski et al., 2018).
their application to sequence generation is largely unexplored.