Summary
In this chapter, we just touched a bit on the very interesting and dynamic field of MARL. There are lots of things that you can try on your own using the MAgent environment or other environments (like PySC2).
My congratulations on reaching the end of the book! I hope that the book was useful and you enjoyed reading it as much as I enjoyed gathering the material and writing all the chapters. As a final word, I would like to wish you good luck in this exciting and dynamic area of RL. The domain is developing very rapidly, but with an understanding of the basics, it will become much simpler for you to keep track of the new developments and research in this field.
There are many very interesting topics left uncovered, such as partially observable Markov decision processes (where environment observations don't fulfill the Markov property) or recent approaches to exploration, such as the count-based methods. There has been a lot of recent activity around multi-agent methods...