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SegreClasses :: segreDimX

segreDimX -- This method computes the dimension X part of the Segre class of a scheme X inside a scheme Y, where X,Y are subschemes of some product of projective spaces

Synopsis

Description

For subschemes X,Y of ℙn1x...xℙnm this command computes the dimension X part of the Segre class s(X,Y) of X in Y as a class in the Chow ring of ℙn1x...xℙnm. This is faster than computing the entire Segre class.

R = makeProductRing({2,2})
x = gens(R)
Y = ideal(random({2,2},R));
X = Y+ideal(x_0*x_3+x_1*x_4);
A = makeChowRing(R)
time s = segreDimX(X,Y,A)
time segre(X,Y,A)

Ways to use segreDimX :