I will be transferring to a different university this fall and I am trying to decide the following: I am somewhat interested in math and am thinking of double majoring in it. However, I would only take math to complement my physics education. I am interested in learning group theory and differential geometry and topology as I know the most interesting physics is based on it. However, if I were to double major, it would require me to take an extra semester to finish. As I understand most graduate schools only accept Fall semester applications so I would basically be losing a year in the process. So do you guys think this would be worth it? Or is it better to just take more physics electives, graduate in 2 years, and take the math that I would have been taking as an undergrad in grad school? I know that most graduate level physics programs provide mathematical physics courses which cover group theory and diff geometry. Also the other thing is that there are several physics electives that I wouldn't be able to take unless I took an extra semester since they have numerous prerequisites (such as solid state physics), so would this be a bad thing? Or could I just take those courses when I go to grad school and really figure out what it is I want to specialize in? Thanks.