I have a question related to set theory.
If $A_1,A_2,A_3\dots, A_n$ belongs to universal set $U$, and if all of the sets are disjoint i.e. $A_i \cap A_j = \emptyset$ for all $i$ and $j$.
And If their union equals to Universal set i.e. $A_1 \cup A_2 \cup \dots A_n = U $ = Universal set.
What is such situation called?