# MultiprojectiveVariety + MultiprojectiveVariety -- union of two multi-projective varieties

## Synopsis

• Operator: +
• Usage:
X + Y
• Inputs:
• Outputs:
• , the union of X and Y, that is, the projective variety defined by the intersection of the corresponding ideals

## Description

 i1 : O = 0_(PP_(ZZ/101)^{2,1}); o1 : ProjectiveVariety, empty subscheme of PP^2 x PP^1 i2 : X = random({2,1},O); o2 : ProjectiveVariety, surface in PP^2 x PP^1 i3 : Y = random({1,1},O); o3 : ProjectiveVariety, surface in PP^2 x PP^1 i4 : Z = X + Y; o4 : ProjectiveVariety, surface in PP^2 x PP^1 i5 : assert(Z \ X == Y and Z \ Y == X)