An overview of LCS research from IWLCS 2019 to 2020.

The International Workshop on Learning Classifier Systems (IWLCS) is a yearly workshop at the GECCO conference where new concepts and results all around Learning Classifier Systems (LCSs) are presented and discussed. One recurring part of the workshop agenda is a presentation that reviews and summarizes the advances made in the field over the last year; this is intented to provide an easy entry point to the most recent progress and achievements. As organizers of the upcoming IWLCS, we take the underlying idea a bit further and accompany the presentation with the present workshop paper, hoping that this recurs as well. We give an overview of all the LCS-related publications since the last IWLCS, that is, since 13th July 2019 and until 10th March 2020. The 33 publications we review are clustered into six overall topics: Formal theoretic advances, approaches that combine LCSs with neural networks, contributions to LCS-based reinforcement learning, improvements to existing LCSs, new LCS architectures and applications of LCSs.