Let A, B, C be sets.
Here's my attempt:
Suppose then and and
So, x is in A not B or C, therefore (is this explanation sufficient?):
Conversely, let , which means and or and
(I'm not sure what to explain here!)
I appreciate it if anyone could help me with this. Thanks.
1) in neither B nor C. and
2) in B but not C
3) in C but not B
In all three cases we see it is in the set on the right.
See if you can go the other way, hopefully now that you understand what that left set actually is, you can get it. Otherwise the proof above me is spot on, but thought I would go through the proof the way you were trying to do it.