I am studying physics and like math. I just finished courses in mathematical logic and probality theory and attended courses in calculus and linear algebra. I intend to learn theoretical informatics next semester. Any more suggestions for interesting mathematics? I started algebra this semester but dropped it because of my other commitments.
Sadly my university does not offer combinatorics. It does not seem to be as interesting as logic, at least if it is anything like the bit of combinatorics one learns with probability theory. Generally, the more fundamental or philosophically relevant a part of math is the more interesting it seems to me.
If your university offering a topic as a course is a prerequisite for you, you might be able to narrow down LW's suggestions by listing which mathematical courses are open to you.