Basic sets

I'm having problems with questions g) and k).

For g), apparantly the answer is i) but it seems to me they're all the same.If |b'| is a finite subset of an infinite set, then |b| must be an infinite set as N is infinite. Is there any difference between saying "b is infinite" and "|b| = infinity"?

For k), apparantly the answer is i) as well, but I still don't understand the notation. Could someone explain it through?.

Page in question: http://i38.tinypic.com/142ev41.jpg

>>35

I'm totally with you!! I was annoyed by the Linear Algebra too, looking at my breakdown I only managed 3 betas in it, hah. On most of the past years' papers I had managed at least 2 alphas overall. I picked up my marks in GRM, CATAM and Anal II.

Ben Green is the young upstart who took the year below us for M&TS, right? Seems like he was intent on making the questions pretty obscure!

I do remember there being a mapping in Comp Methods now. I'm not sure why I didn't attempt it... did it have a bit that wasn't very standard?