Sets Union of sets:SUT,USi,Uie Si. Intersection of sets:SnT,nSi,nie Si. Disjoint sets:empty pairwise intersection. Partition of set S:a collection of disjoint sets whose union is S. De Morgan's laws: U:S=∩：S,∩S=U:SSets ◼ Union of sets: 𝑆 ∪ 𝑇, ڂ=��1 ∞ 𝑆𝑖 �𝑆� ��∋��ڂ , . ◼ Intersection of sets: 𝑆 ∩ 𝑇, ځ=��1 ∞ 𝑆𝑖 �𝑆� ��∋��ځ , . ◼ Disjoint sets: empty pairwise intersection. ◼ Partition of set 𝑆: a collection of disjoint sets whose union is 𝑆. ◼ De Morgan’s laws: ��ڂ ��ഥ𝑖 𝑆ځ = �𝑆� ��ځ , ��ഥ𝑖 𝑆ڂ = �𝑆�