what are A and B? Are these sets? Numbers? is || cardinality of sets or absolute value? If they are sets what do you mean A/B are these cosets or what? As it stands your question makes 0 sense to me.
I need to prove this:
if |A\B|=|B\A| then |A|=|B|
The only thing I can see is that this means that I can create a surjective (onto) +injective (one-to-one) function from A to B.
How can I continue solving this?
Thank you very much !
Well I really appreciate your good wish to help, but since I posted this on the wrong forum I really couldn't expect to recieve the most percise answers for my problem.
After posting this on the right forum, I got a more percise answer which included ways of solving it that are in my studying material.
Thank you very much anyway