universe (variable)
The set containing all entities under consideration.
Description
If the programmer assigns a set to the universe variable, which may not exist prior to that assignment, then this set will be used as the universe by the ∁ operator (and the complement) function.
Examples
universe ≔ ToSet(SequenceList(0, 10))
{8, 6, 10, 2, 9, 3, 4, 5, 1, 7, 0}
A ≔ { 1, 2, 3, 4, 5 }
{4, 5, 1, 2, 3}
∁A
{7, 6, 10, 9, 8, 0}