Practice problem
Let AAA and BBB be sets. Which of the following are always true?
A∩B⊆A∪BA \cap B \subseteq A \cup BA∩B⊆A∪B
A∪B⊆A∩BA \cup B \subseteq A \cap BA∪B⊆A∩B
A⊆BA \subseteq BA⊆B if and only if A∪B=BA \cup B = BA∪B=B
A⊆BA \subseteq BA⊆B if and only if A∩B=AA \cap B = AA∩B=A
A∪B⊆A∩BA \cup B \subseteq A \cap BA∪B⊆A∩B if and only if A=BA = BA=B
A∪(B∩∅)⊈BA \cup (B \cap \varnothing) \not\subseteq BA∪(B∩∅)⊆B
Type a concept, like “slope” or “photosynthesis”.