The first time I took Electromagnetics via Jackson I did terribly on account of not knowing the math needed to read the book (I despise the fact that many graduate programs do not specify what math is genuinely needed to read the textbooks they assign). At the time, I had taken 1 course each in Multivariable Calculus, Matrix Algebra, introductory analysis, ODEs, PDEs, and a Math Methods course in my undergrad physics department. I unfortunately found out that this is nowhere near enough to get through Jackson; one needs to know Green functions quite well, quite a bit about tensors, Fourier analysis, and complex analysis. Beyond the topics I have mentioned, what topics in mathematics are necessary to read Jackson and understand it meaningfully? Additionally, I have discovered, to my disdain at not being told this ahead of time again, that to understand Quantum Mechanics I and II, one does need to know beginner abstract algebra/algebraic structures. What areas of math are recommended to read a QM textbook meaningfully for general first year graduate quantum mechanics beyond what is already mentioned?