ideal(MultiprojectiveVariety) -- the defining ideal of the variety

Synopsis

• Function: ideal

• Usage:

  ideal X

• Inputs:
  • X, a multi-projective variety
• Outputs:
  • an ideal, the defining ideal of $X$

Description

i1 : X = PP_QQ^({2,1},{1,3});

o1 : ProjectiveVariety, threefold in PP^2 x PP^3

i2 : ideal X

              2                              2
o2 = ideal (x1  - x1 x1 , x1 x1  - x1 x1 , x1  - x1 x1 )
              2     1  3    1  2     0  3    1     0  2

o2 : Ideal of QQ[x0 ..x0 , x1 ..x1 ]
                   0    2    0    3

See also

• ring(MultiprojectiveVariety) -- the coordinate ring of the variety