A set is:
The objects element of the set have the same type (the type may be a composed type such as a tuple)
The mathematical concept of a set is a group of unique items, meaning that the group contains no duplicates (theory) but many data application have extended this definition with a bag (multiset) (such as a table)
The set is used to perform distinct operation (ie deleting duplicates)
Some real-world examples of sets include the following:
The basic properties of sets:
In Mathese, “the set of non-negative numbers” is written like this:
where:
The above notation can also be shortened if x is wel known :
Another example where the set consists of and
Tuples examples in set expression:
the square of the first can be written:
of abbreviated: