Justifying your conclusions (you could also use examples in order to illustrate your results).

Question

What can you say about the sets A and B if we know that:

1. A ∪ B = A
2. A ∩ B = A

Thanks for any helpful replies :)

Answer 1

1. A∪B = A
=> x∈B -> x∈A
=> B⊆A

2. A∩B = A
=> x∈A -> x∈B
=> A⊆B

Now
B⊆A ∧ A⊆B
means what?