In this example we compute the number of lines meeting four lines in space.
i1 : G = flagBundle {2,2} o1 = G o1 : a flag bundle with subquotient ranks {2:2} |
i2 : dim G o2 = 4 |
i3 : A = intersectionRing G o3 = A o3 : QuotientRing |
i4 : f = (chern_1 OO_G(1))^4 2 o4 = 2H 2,2 o4 : A |
i5 : integral f o5 = 2 |
Normally this integral will be an element of the intersection ring of point, and thus will essentially be a rational number, but it could be in any base variety, and would be obtained by pushing forward along the structure maps of flag bundles until the (ultimate) base variety is reached.
i6 : pt = base n o6 = pt o6 : an abstract variety of dimension 0 |
i7 : F = flagBundle_{2,2} pt o7 = F o7 : a flag bundle with subquotient ranks {2:2} |
i8 : integral (chern_1 OO_F(n))^4 4 o8 = 2n o8 : QQ[n] |
The object integral is a method function.