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MultiprojectiveVarieties :: MultiprojectiveVariety ** Ring

MultiprojectiveVariety ** Ring -- change the coefficient ring of a multi-projective variety

Synopsis

Description

It is necessary that all multi-forms in the old coefficient ring F can be automatically coerced into the new coefficient ring K.

i1 : use ring PP_QQ^{2,3};
i2 : X = projectiveVariety ideal(x1_2^2-x1_1*x1_3,x1_1*x1_2-x1_0*x1_3,x1_1^2-x1_0*x1_2,x0_1^2-x0_0*x0_2);

o2 : ProjectiveVariety, surface in PP^2 x PP^3
i3 : ideal X

              2                              2             2
o3 = ideal (x1  - x1 x1 , x1 x1  - x1 x1 , x1  - x1 x1 , x0  - x0 x0 )
              2     1  3    1  2     0  3    1     0  2    1     0  2

o3 : Ideal of QQ[x0 ..x0 , x1 ..x1 ]
                   0    2    0    3
i4 : K = ZZ/65521;
i5 : X' = X ** K;

o5 : ProjectiveVariety, surface in PP^2 x PP^3
i6 : ideal X'

              2                              2             2
o6 = ideal (x1  - x1 x1 , x1 x1  - x1 x1 , x1  - x1 x1 , x0  - x0 x0 )
              2     1  3    1  2     0  3    1     0  2    1     0  2

o6 : Ideal of K[x0 ..x0 , x1 ..x1 ]
                  0    2    0    3

See also