Prove each of the following results without using Venn diagrams or membership tables. (Assume a universe .)
a) If A ⊆ B and C ⊆ D, then A ∩ C ⊆ B ∩ D and A ∪ C ⊆ B ∪ D.
b) A ⊆ B if and only if .
c) A ⊆ B if and only if .
We need at least 10 more requests to produce the solution.
0 / 10 have requested this problem solution
The more requests, the faster the answer.