“…The new types of decision trees proposed in Chapter 8, which operate on state-action pairs as inputs, are a first step towards extending previous work on explaining RL-based policies (Coppens et al, 2019(Coppens et al, , 2021Deproost, 2021) to domains with large action spaces. Explainability in games (Silva et al, 2021;Pálsson and Björnsson, 2022;Stephenson et al, 2022), search Kaisers, 2020, 2021), RL (Liu et al, 2019;Hilton et al, 2020;Lin et al, 2021), and AI more gen-IMPACT PARAGRAPH 275 erally (Molnar, 2020;Zhang et al, 2021), are increasingly recognised as crucial fields of research.…”