Here is my situation: I am currently finishing my undergraduate physics program and thinking of doing graduate studies. My only concern is that the knowledge of mathematics is fairly weak. My program offers little mathematics, its very general physica. I am interested in doing theoretical physics in the domain of cosmology, quantum mechanics or particle physics (something to that effect). As I am aware, these subjects are heavily based on mathematics. Here is my question: I have a good long break coming up and was hoping to get some studying done. Can someone give me a list of mathematical topics/applications I may want to study to enhance my skills in the mathematical side of physics?