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

• Operator: +

• Usage:

  X + Y

• Inputs:
  • X, a multi-projective variety
  • Y, a multi-projective variety
• Outputs:
  • a multi-projective variety, the union of X and Y, that is, the projective variety defined by the intersection of the corresponding ideals

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)