What would be the prerequisites to understand the material in this book ? It is advertised as an undergraduate course, but it seems this would apply to either very dedicated or quite advanced students after reading the first pages.
https://math.berkeley.edu/~frenkel/loop.pdf
Would one need representation theory, elements of algebraic number theory ,modular forms and some Lie group theory, as explained in this answer https://math.stackexchange.com/q/49179 or is Frenkel's book truly a more accessible introduction ?