<p>Collegealum, it seems Math 55 requires not so much in terms of raw prerequisites as maturity, i.e. you should already be well-seasoned in reading and communicating mathematics. </p>
<p>OP – your concern about collaboration is definitely legitimate, but as I said, pick the school that’s right for you, and worry about 55 if you’re going to MIT or Harvard. I know that MIT is a very good topology school. </p>
<p>However, oddly enough if you’re interested in set theory or logic, Berkeley is supposed to be really amazing (I say this impartially as well, because I can’t bring myself to get into that type of material). Then again, unless you’re really really set on this stuff, I’d not base undergraduate decisions on such things.</p>
<p>EDIT – something tells me you should choose MIT, OP :)</p>