Рет қаралды 21
xic
38. Prove that for all sets the following are valid.(a) (A ⊆ C & B ⊆ C) ⇔ (A ∪ B ⊆ C).(b) (C ⊆ A & C ⊆ B) ⇔ (C ⊆ A ∩ B).