topComponents(MultiprojectiveVariety) -- union of the top dimensional components of a multi-projective variety

Synopsis

• Function: topComponents

• Usage:

  top X

• Inputs:
  • X, a multi-projective variety
• Outputs:
  • a multi-projective variety, the union of the top dimensional components of X

Description

i1 : K = ZZ/65521;

i2 : X = (linearSpan {point PP_K^4,point PP_K^4}) + (point PP_K^4);

o2 : ProjectiveVariety, curve in PP^4

i3 : top X

o3 = curve in PP^4 cut out by 3 hypersurfaces of degree 1

o3 : ProjectiveVariety, curve in PP^4

i4 : assert(top top X === top X)

See also

• decompose(MultiprojectiveVariety) -- irreducible components of a variety
• topComponents(Ideal) -- compute top dimensional component of an ideal or module