Mathematics for physicists

I was thinking of double majoring with mathematics to complement my bachelor's in physics, but this would end up extending my graduation by a year (two semesters), cost more tuition over my financial aid, and make me double up/ add another class onto my normal fall/spring credits. Would I just be better off studying more mathematics on my own time during the summer to be better prepared for graduate school? If anything I'd love to study both in graduate school but I don't really think I can juggle both at this point of academia. Again, just for my bachelor's.

>>4
As an undergrad, I've been lectured by at least two eminent mathematicians whose area of interest has centred strongly on Representation Theory. Maybe the mathematical community as a whole has disdain for it, but there are plenty of competent guys doing work with it.

>>4
>representation theory, which mathematicians completely ignore

Modern number theory is all about representation theory.

http://en.wikipedia.org/wiki/Langlands_program

>>4
I'm doing a rep theory course as an undergrad.

Fucking thing seems so easy and so hard at the same time :(