i1 : ZZ/65521[x_0..x_4], f = rationalMap {x_3^2-x_2*x_4,x_2*x_3-x_1*x_4,x_1*x_3-x_0*x_4,x_2^2-x_0*x_4,x_1*x_2-x_0*x_3,x_1^2-x_0*x_2};
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i2 : Phi = multirationalMap {f}
o2 = Phi
o2 : MultirationalMap (rational map from PP^4 to PP^5)
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i3 : check Phi
o3 = Phi
o3 : MultirationalMap (rational map from PP^4 to PP^5)
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i4 : Y = image Phi
o4 = Y
o4 : ProjectiveVariety, hypersurface in PP^5
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i5 : Psi = multirationalMap({f},Y)
o5 = Psi
o5 : MultirationalMap (rational map from PP^4 to hypersurface in PP^5)
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i6 : check Psi
o6 = Psi
o6 : MultirationalMap (rational map from PP^4 to hypersurface in PP^5)
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i7 : p = point Y;
o7 : ProjectiveVariety, 0-dimensional subvariety of PP^5
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i8 : Eta = multirationalMap({f},p);
o8 : MultirationalMap (rational map from PP^4 to 0-dimensional subvariety of PP^5)
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i9 : try check Eta else <<"meaningless object!";
meaningless object!
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