“…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. The successful results in terms of producing stronger agents through feature selection are furthermore of interest to game AI and RL research in general.…”