Usage:
<line_bundle_image m y j
Find the equations, "j", of the image to projective space defined by
the line bundle which is the sheafification of the module "m",
on the projective scheme X = Supp(m). The variables of this
new projective space are named y[0], ..., y[r].
Parameters:
m = a matrix whose sheafification is a line bundle on X.
y = a letter. The variables in the base ring of the result are
y[0], ..., y[r], for some r.
Output values:
j = the ideal in y[0], ..., y[r] defining the image to P^r
of the map corresponding to the elements of "m" of degree zero.
See the forthcoming paper by M. Brundu and M. Stillman for a more
detailed description and proof of this method.
Caveats: If the module "m" is not reflexive (or "S2"), then the
elements of degree zero in m might not generate the entire vector space
of global sections of the line bundle. This script will compute the
image using exactly these section. You might wish to first use
"double_dual" on the module "m".