Here's the question, for my degree at the U of C I have to take Phys323 at some point, so I check it out, and it lists Prerequisites and in a separate section it has a Corequisite of Math253. However, when I check Math253, it lists no Corequisites! WTF is going on??? Do I need to take those two classes at the same time, or is it okay if I take them at separate times?