Commit 6fdf08fb authored by Peter Bruin's avatar Peter Bruin

document torsion_data

parent c5c36129
......@@ -173,12 +173,24 @@ iso(GEN X, GEN c, GEN D, GEN W_E, GEN s, GEN u, GEN v) {
return gerepileupto(av, ginv(gmul(gel(gamma, m + 1), delta)));
}
/*
Input:
W_D, W_D0: subspaces defining divisors D, D_0 such that
{\cal L}(-D_0) is trivial and {\cal L}(-D) is of order n
c = [[i_2, j_2], ..., [i_m, j_m]]: addflip chain for n
Output:
[D_0, D_1, ..., D_m]: divisors of degree d
[s_2, s_3, ..., s_m]: sections of {\cal L}^3 with
div(s_l) = D_{i_l} + D_{j_l} + D_l
v: section of {\cal L} with div(v) = D_m
*/
static void
torsion_data(GEN J, GEN W_D, GEN W_D0, GEN c,
GEN *D, GEN *s, GEN *v) {
long i, j, l, m = lg(c);
*D = cgetg(m + 2, t_VEC); /* D_i = gel(*D, i + 1) */
*D = cgetg(m + 2, t_VEC);
*s = cgetg(m, t_VEC);
gel(*D, 1) = W_D0;
gel(*D, 2) = W_D;
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment