A
partition of a
set X is a set
P of nonempty
subsets of
X such that
every element
x in
X is in exactly one of these subsets.
Examples:
- The set {1, 2, 3} has the following partitions
- { {1}, {2}, {3} },
- { {1, 2}, {3} },
- { {1, 3}, {2} },
- { {1}, {2, 3} } and
- { {1, 2, 3} }.
- Note that { {}, {1,3}, {2} } is not a partition because it contains an empty subset and { {1,2}, {2, 3} } is also not a partition because the element 2 is contained in more than one subset.
See also: