sup(I) : range -> constantsup(x) : constant -> constant
Parameters:
I is an interval.
x is a real number.
Description:
Returns the upper bound of the interval I. Each bound of an interval has its
own precision, so this command is exact, even if the current precision is too
small to represent the bound.
When called on a real number x, sup considers it as an interval formed
of a single point: [x, x]. In other words, sup behaves like the identity.