i1 : ZZ/65521[x_0..x_4]; |
i2 : Psi = multirationalMap {last graph rationalMap({x_2^2-x_1*x_3, x_1*x_2-x_0*x_3, x_1^2-x_0*x_2, x_0*x_4, x_1*x_4, x_2*x_4, x_3*x_4, x_4^2},Dominant=>true)}; o2 : MultirationalMap (dominant rational map from 4-dimensional subvariety of PP^4 x PP^7 to 4-dimensional subvariety of PP^7) |
i3 : Phi = first graph Psi; o3 : MultirationalMap (birational map from 4-dimensional subvariety of PP^4 x PP^7 x PP^7 to 4-dimensional subvariety of PP^4 x PP^7) |
i4 : Eta = Phi * Psi; o4 : MultirationalMap (dominant rational map from 4-dimensional subvariety of PP^4 x PP^7 x PP^7 to 4-dimensional subvariety of PP^7) |
i5 : assert(Eta == last graph Psi); |