This is the one I am having the most trouble with, thanks in advance.

Determine, by any means, whether the following argument is valid or not:

"If a set A is a proper subset of another set B, then the intersection of A and B is also a proper subset of B; but A is equal to B or B is a proper subset of A; hence the intersection of A and B is a proper subset of A."

Before I try using LaTex to start the problem, is the file really a whole gig...heh.