Out of curiosity, I was looking at core course requirements for the PhD in physics at several different schools. I noticed that some schools required a first semester math methods while others do not. Reading the course descriptions, I noticed some overlap between topics usually seen at the undergrad level (Fourier analysis, series solutions to DEs) as well as some more advanced topics (Green's functions, complex analysis). I am curious if the majority of the physics grad students and degree holders on this forum were give a math methods course in their first year of grad study. If you did, did you think that this course was absolutely necessary before undertaking the rigors of the rest of the common physics core? Or was it more helpful but necessarily a requirement? I am also curious what the common text(s) is for this type of course. Other comments are always welcomed!