next | previous | forward | backward | up | top | index | toc | Macaulay2 web site
RationalMaps :: dimImage

dimImage -- Computes dimension of image of rational map of projective varieties

Synopsis

Description

Gives the dimension of the image of a rational map. It should be noted for inputs that all rings are quotients of polynomial rings, and all ideals and ring maps are of these

i1 : S = QQ[x,y,z,w];
i2 : b = ideal(x*y-z*w);

o2 : Ideal of S
i3 : R = QQ[u,v];
i4 : a = ideal(sub(0,R));

o4 : Ideal of R
i5 : f = matrix {{u,0,v,0}};

             1       4
o5 : Matrix R  <--- R
i6 : dimImage(a,b,f)

o6 = 1

Ways to use dimImage :