Two sets 
and 
are disjoint if their intersection 
, where 
is the empty
set. 
sets 
,
, ..., 
are disjoint if 
for 
. For example, 
and 
are disjoint, but 
and 
are not. Disjoint sets are also said to be mutually
exclusive or independent.
Disjoint Sets
See also
Empty Set, Independent Set, Intersection, SetExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Disjoint Sets." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/DisjointSets.html