What is the mathematical notation for a group of pairwise disjoint sets? Assume I have 4 sets: $A$, $B$, $C$, and $D$. What is the mathematical notation to indicate that all of these sets are _pairwise_ disjoint? I can obviously type: $$A \cap B = \emptyset$$ $$A \cap C = \emptyset$$ etc. But I am looking for a more succinct and mathematically correct way of expressing this.

If you have indexed family $\\{A_i\\}_{i\in I}$, then you can write $A_i\cap A_j=\emptyset$, $i\
eq j$. If not, I don't see any problem in just stating: "Let $A,B,C,D$ be pairwise disjoint." This will probably be more clear than any notation you could come up with, including my own suggestion.