D.5.8.18 tangentcone

Procedure from library sing.lib (see sing_lib).

Usage:

tangentcone(id [,n]); id = ideal, n = int

Return:

the tangent cone of id

Note:

the procedure works for any monomial ordering.
If n=0 use std w.r.t. local ordering ds, if n=1 use locstd

Example:

LIB "sing.lib";
ring R = 0,(x,y,z),ds;
ideal i  = 7xyz+z5,x2+y3+z7,5z5+y5;
tangentcone(i);
→ _[1]=x2
→ _[2]=7xyz
→ _[3]=y5+5z5
→ _[4]=7y4z
→ _[5]=35z6