next | previous | forward | backward | up | top | index | toc | Macaulay2 website
MultiprojectiveVarieties :: check(MultirationalMap)

check(MultirationalMap) -- check that a multi-rational map is well-defined

Synopsis

Description

i1 : f = rationalMap ideal PP_(ZZ/65521)^(1,4);

o1 : RationalMap (quadratic rational map from PP^4 to PP^5)
i2 : Phi = rationalMap {f}

o2 = Phi

o2 : MultirationalMap (rational map from PP^4 to PP^5)
i3 : check Phi

o3 = Phi

o3 : MultirationalMap (rational map from PP^4 to PP^5)
i4 : Y = image Phi

o4 = Y

o4 : ProjectiveVariety, hypersurface in PP^5
i5 : Psi = rationalMap({f},Y)

o5 = Psi

o5 : MultirationalMap (rational map from PP^4 to Y)
i6 : check Psi

o6 = Psi

o6 : MultirationalMap (rational map from PP^4 to Y)
i7 : p = point Y;

o7 : ProjectiveVariety, a point in PP^5
i8 : Eta = rationalMap({f},p);

o8 : MultirationalMap (rational map from PP^4 to p)
i9 : stopIfError = false;
i10 : check Eta
stdio:10:1:(3): error: the target variety is not compatible with the maps

See also