# Interval -- a class of all intervals

## Description

This type is a new type of List. The function interval can be used to access an Interval.

 i1 : I = interval(.5,.8) o1 = [.5, .8] o1 : Interval

Users can make an interval which has polynomials as entries.

 i2 : R = QQ[x]; i3 : J = interval(5,3*x) o3 = [5, 3x] o3 : Interval

NumericalCertification supports some basic interval arithmetics.

 i4 : I1 = interval(.5,.8); i5 : I2 = interval(.6,.9); i6 : I1 + I2 o6 = [1.1, 1.7] o6 : Interval i7 : I1 - I2 o7 = [-.4, .2] o7 : Interval i8 : I1 * I2 o8 = [.3, .72] o8 : Interval i9 : I1 / I2 o9 = [.555556, 1.33333] o9 : Interval i10 : I1 ^ 3 o10 = [.125, .512] o10 : Interval

## For the programmer

The object Interval is a type, with ancestor classes List < VisibleList < BasicList < Thing.