math
posted by Fakaapo. Suetusi .
What can you say about sets A and B if you know that.
1)A U B = A?
2)A ¿ B = A?
3)A  B = A?

1. A ⊇ B , B is a subset of A
2. not familiar with the operator ¿ in sets
3. Did not know that "" was an operator with sets 
I assume 2) is intersection
If the intersection of A and B = A, then A is a subset of B.
AB is the members of A that are not in B. If that is equal to A, then B is empty. 
Hmmm. On that last one, AB=A means that A and B are disjoint, or B is empty.